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Illustration of a German parchmenter from 1568

The conservation and restoration of parchment constitutes the care and treatment of parchment materials which have cultural and historical significance. Typically undertaken by professional book and document conservators, this process can include preventive measures which protect against future deterioration as well as specific treatments to alleviate changes already caused by agents of deterioration.

Parchment manufacturing and properties

The making of parchment in the Netherlands

Parchment is the skin of an animal, usually sheep, calf or goat, which has been dehaired, processed with a lime solution and stretched under tension. The dried material is a thin membrane which is most commonly used as a writing surface, but can also be used to make other items like bookbindings and drumheads. Throughout Europe, parchment was the primary writing substrate from its development in the 2nd century BCE through the Middle Ages, though it is used through the present day for various official documents.^[1] Typically parchment made from calfskin is called vellum, though the term can also be used to refer to very fine quality parchment made from the skins of other animals. For the purposes of conservation and restoration, the term parchment is used in reference to vellum objects, as the terms have been used interchangeably throughout time to refer to objects with the same conservation concerns.^[2]

Parchment has unique structural qualities which differentiate it from paper-based materials. Typically, parchment is resistant to mechanical damage like tears or creasing, though it is easily susceptible to damage from mold and high temperatures.^[2] Parchment is also highly hygroscopic in nature, meaning that changes in relative humidity can cause irreversible variations to its structural makeup. ^[3] These specific qualities dictate the conservation and restoration treatments required for parchment.

Physical and chemical properties

Most skins used for parchment are 1–3 mm in thickness before processing. Animal skin used for parchment all has the same basic structure, with slight variations due to the species, age and diet of the specific animal. Skin is composed of innumerable fibrils made up of the protein collagen, which are held in bundles that interweave in a three dimensional manner through the skin. The fibrous material is composed of many long chain molecules of collagen, which can react with certain environmental factors. One universal property of collagen is that it exhibits sudden shrinkage when heated in water, starting at 65 °C (149 °F). Prolonged exposure to alkali, like in parchment liming process, changes the amino acids, consequently dropping shrinkage temperatures as low as 55 °C (131 °F).^[4]

Manufacturing

Once it is removed from the animal, the skin is temporarily preserved, either by drying or liberal application of salt, until it can be processed. The skin is then immersed in water for 48 hours, which cleans and rehydrates it. This step also removes the non-collagenous materials, like hyaluronic acid, dermaten sulphate and plasma proteins. The skin is then soaked in a lime or alkali solution, known as the liming process.^[4] In the 19th century, chemicals were added to speed up the liming process, which resulted in weaker parchments. These added compounds sometimes reacted to produce gypsum, giving the parchment a characteristic gray hue.^[5] The skin is then stretched in suspension on a frame, constricting it as it dries. This ensures even contraction across the entire parchment which ensures that it will remain flat when dried.^[6] After being prepared, parchment is sometimes coated so that it is more receptive to pigment and ink. Historical coatings, which include chalk, egg whites and matte paint, must be taken into consideration as a meaningful part of the preservation and conservation plan.^[2]

The manufacturing process, which removes the skin's natural fats and oils, means that parchment is more reactive to moisture and relative humidity than other skin-based material. After being stretched, parchment has an inherent desire to revert to its original animal shape, especially if left unrestrained or exposed to repeated changes in relative humidity.^[7]

Identification

Parchment is usually positively identified by sight, sometimes with the assistance of a hand lens or microscope. Visible hair follicle pattern, veining, scars, bruises and sometimes fat deposits all help confirm the animal origin of the material. Additional light sources including ultraviolet lights, can make these properties more easily identifiable.^[8]

Sometimes visual examination is not sufficient to distinguish parchment from certain types of highly calendered papers. Misidentification of these materials can lead to inappropriate preservation methods or conservation treatments.^[2] Analytical testing, which involves removing a small piece of parchment, can be done by or under the supervision of a professional conservator-restorer to ensure positive identification. One type of analytical testing involves examining the parchment specimen under a light microscope or scanning electron microscopy. A simple flame test can also be done on the parchment specimen; true parchment will emit the meaty smell of burned protein, while other look-alike materials will smell like paper or wood.^[9]

Agents of deterioration

Relative humidity changes^[10]

Changes in relative humidity can cause parchment to change shape, especially if movement is restrained by a frame or mount at certain parts of the object, which leads to uneven distortion. This distortion can result in cockling and destabilization of any pigments affixed to the parchment.^[11] Low humidity levels can cause parchment to desiccate.^[12]

Water and excessive moisture

Direct water contact and excessive moisture in the environment can cause structural problems for parchment including: expansion of object; discoloration; alteration of surface coatings; gelatinization of skin; and realignment of fibers.^[2]

Oxygen

Atmospheric oxygen reacts with the chemical composition of parchment, which subsequently changes the physical properties of the object over time.^[13]

Mold

Mold is a probable consequence of water damage to parchment, especially when the object is not dried within 48 hours of the initial contact with water.^[14]

Heat:

Heat in excess of the ideal storage conditions can cause damage to collagen structure, irreversible contraction and alteration of surface materials in parchment objects.^[2]

Light exposure

Lower wavelength and ultraviolet light lead to degradation of the collagen structure and photodiscoloration, usually causing yellowing of parchment.^[4] Parchment exposed to UV light can also have a photochemical reaction causing it to become brittle.^[5]

Flaking and friability

Consolidation of media on parchment, such as those found in illuminated manuscripts, is compromised by the instability of the parchment substrate. Excessive flexing or chemical changes in the parchment can lead to loss of pigment and text.^[15]

Poor storage

Parchment which has been adhered to a rigid mount for storage or display is unable to expand and contract, as its natural tendency. This poor storage technique can lead to tears, perforations and loss. Parchment stored in an unregulated and inconsistent environment is more susceptible to damage.^[12]

Storage and preventive care

Proper storage environments can help ward off structural, chemical and environmental changes which affects the long-term preservation of parchment. Storage factors must take into account the factors of the particular parchment object, including its condition, age, storage history and plans for use. Illuminated manuscripts and composite parchment objects, which may include seals and ribbons, may have additional storage needs.^[2] A consistent storage environment is crucial for the long-term stability of parchment, which is especially vulnerable to changes in humidity, temperature and other environmental factors.^[11]

Microenvironments are less expensive ways to provide consistent storage environments for parchment if the external storage conditions are not ideal. Moisture sensitive parchments can be stored in a Plexiglas sandwich by inserting the matted parchment between two sheets of acrylic and taping off all sides. Parchment can also be stored in envelopes constructed out of polyester sheets.^[16]

For the long-term preservation of organic material like parchment, the ideal temperature range is 10–15 °C (50–59 °F) with a relative humidity level of 30–50%. The ideal storage and display environment is oxygen-free, as oxygen prevalence has been shown to react with collagen over time, leading to increased brittleness of parchment. Oxygen-free storage and display cases are filled with inert gas as well as a chemical substance that reacts as an absorber if any stray oxygen leaks into the encasement.^[13]

Ethical concerns of conservation

The American Institute for Conservation's Code of Ethics and Guidelines for Practice set forth the conduct for conservation and restoration treatments of parchment objects.^[17] The hazards of specific treatments need to be weighed against the benefits, as many traditional liquid-based conservation techniques can pose risks to parchment.^[18]

Conservation treatments

Removal of previous restorations

Previous repairs and conservation treatments are removed if it is determined that the parchment is in good condition and that the repair is not of historic importance to the parchment. Dried out patches are removed via cleaning and humidification techniques. Parchment objects that have been attached to mounts are removed with a sharpened lifting tool and a small amount of moisture. Previous laminations, like Goldbeater's skin and Mipofolie, can sometimes be removed with solvents and mechanical techniques, though this removal technique can risk additional damage to the original parchment.^[2]

Cleaning

Surface cleaning of parchment has been developed after methods used for cleaning paper, with a few key differences related to the structural and chemical properties of parchment. For the most part, chemical treatments are ineffective and some, like hypochlorites and methyl bromide, can denaturalize parchment. Prior to cleaning, any flaking or vulnerable media is consolidated to ensure it does not detach from the parchment substrate. Consolidation of parchment media is undertaken by applying various dilute adhesives like isinglass, gelatin or parchment size through brush application or by the use of an ultrasonic humidification apparatus.

If their presence is determined upon examination, insects and pests are eliminated and the parchment disinfected. An appropriate round of fumigation in an autoclave is used to remove pests and sterilize the object. Dry and wet cleaning techniques can both be used effectively on parchment objects. Mechanical cleaning using erasers and other abrasive tools is used to remove mildew and dirt. Surface cleaning of parchment is typically completed using white vinyl erasers (solid and grated) and confined to areas where no media is present. Water baths, which sometimes use neutral detergents or alcohol as additives, can be used to clean as well as prepare the parchment for stretching as part of the conservation process.^[19] Another wet cleaning method, which is especially useful for removing mold and mildew, uses a cotton swab covered in fluid, usually denatured alcohol, ethanol or saliva. Laser cleaning may provide a non-contact cleaning process, though conservation labs throughout Europe still mostly use traditional wet and dry cleaning methods for parchment.^[20]

Humidification

Humidification is a parchment conservation treatment which involves the controlled and monitored increase in relative humidity. Humidified parchments are more flexible, which will allow for corrections to distortions like cockling, puckering and changes in original size. Some methods of humidification are: humidification chambers: moisture chambers with ultrasonic humidifier, moisture chambers with steam/ultrasonic mist; and application of alcohol and water. Localized humidification is sometimes used to treat specific folds or creases in parchment objects.^[2]

Flattening, tensioning and drying

After humidification, drying techniques are necessary to ensure that the parchment lays flat and does not suffer additional moisture-related issues. The specific method is dependent on the condition of the object, as well as the humidification process utilized. Some of the most common methods include:

Drying and flattening under pressure, often pressed between two absorbent surfaces
Tensioning at the edges, where the parchment is constricted at the edges with weights or clips. This techniques most closely reflects parchment's original manufacturing process.
Stretch drying on Terylene
Vacuum suction table flattening^[2]

Localized creases are eased with a solution of 80% to 90% isopropyl alcohol and water, which is applied to the creases directly with a cotton swab and then gently pulled flat by hand. The alcohol–water mixture is azeotropic, meaning both components evaporate simultaneously. The solution has a lower surface tension than just water, which causes the fibers to suffer less shrinkage.^[21]

Mending and in-filling losses

Sewing tears is not recommended as a conservation treatment, unless it is replacing a sewn portion original to the object. Correcting non-original splits, tears, perforations and losses in parchment requires careful consideration of its specific condition. For losses that do not require much support, transparent membranes, such as fish skin or sausage casing, are placed over the damaged area with an adhesive. Infill materials, including new parchment, reconstituted parchment and Japanese paper, are used to repair losses requiring greater structural support. All infill materials have some conservation concerns, as they will react differently to environmental factors than the original parchment.

New parchment: It is difficult to match the infill material to the original parchment type in terms of animal, thickness and appearance. Modern parchments that appear visually similar also respond differently to humidity fluctuations, causing potential problems after the conservation treatment. Parchment infills are matched by thinning them to the appropriate size and bevelling the original parchment before the repair.
Japanese paper: Paper is dissimilar to parchment in both appearance and behavior, which can pose the future issue of storing an object with composite materials. Paper infills can be toned with watercolor or acrylic paints to better match the original parchment appearance. Acrylic-toned papers are treated with various adhesives such as B-72, Aquazol, or PVA to mimic the translucency of the surrounding parchment. Varying layers of application are used to best approximate the thickness and condition of the specific original parchment.^[2]
Reconstituted parchment: Collagen fibers and dry cellulose materials are mixed together with liquid ingredients to create a pulp-like substance. This material is applied to the original parchment in a process similar to leafcasting paper.^[22]

Disaster recovery

Parchment which has been accidentally exposed to excess moisture or water is extremely susceptible to mold, mechanical damage and irreversible dimensional changes. Emergencies often affect large quantities of objects, therefore the mass treatment of objects usually includes freezing or freeze-drying as the first step. As time permits, parchment object are then thawed and dried using more traditional measures.^[2]

Case studies

Charters of Freedom

The United States Declaration of Independence, Constitution and the Bill of Rights, collectively known as the Charters of Freedom, were housed in metal and glass encasements, filled with helium gas, from 1952 to 2001.^[23]^[24]^[25] In 1951, the National Bureau of Standards reported that an inert gas environment would be the best means of preserving the Charters of Freedom.^[13] In 1982, the National Archives and Records Administration partnered with the Jet Propulsion Laboratory on a nine-year project which determined that the encasement glass was deteriorating. Upon the issuing of this report, it was decided that new encasements and conservation treatments were needed for the long-term preservation of the Charters of Freedom. The documents were thoroughly examined for signs of deterioration and past restorations, all of which were thoroughly documented in condition reports.^[26]

The first step of treatment stabilized the ink of the text using a gelatin adhesive. The dirt and grime were then cleaned from the parchments, though original intentional marks were left alone. The Constitution and the Bill of Rights were then humidified and dried under tension to flatten the parchments. The Declaration of Independence, which has been damaged by frequent handling and exposure, was not humidified because of its increased moisture sensitivity.^[23] All the parchments were then installed into new titanium and aluminum encasements, developed by the National Institute of Standards and Technology, which are filled with inert argon gas.^[25] The current environmental conditions of the Charters of Freedom encasements is monitored by scientists and conservators for signs of possible deterioration agents.^[24]

Canterbury Magna Carta

In 1731, one of four surviving copies of the 1215 Magna Carta, known as the Canterbury Magna Carta, was partially damaged in a fire at its temporary storage location at Ashburnham House. Damage included shrinkage and discoloration of the parchment substrate, though the ink text was still legible. In the 1830s, British Museum staff attempted a restoration, using chemicals to treat the parchment and unintentionally rendering the text illegible.

In 2014, the British Library undertook a multispectral imaging project to determine if the text on the damaged document could be recovered. Analysis under ultraviolet light allowed scientists and conservators to see text that was invisible to the naked eye. This new technology allows the document to be used for continued research purposes, despite the previous botched restoration.^[27]

References

Notes

^ Whymark, Francesca. "Is not parchment made of sheepskins? Ay, my lord, and of calfskins too..." British Library Collection Care Blog.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l "Parchment Treatments" (PDF). Conservation OnLine. Foundation of the American Institute for Conservation.
^ "Caring for your collections: Parchment documents" (PDF). State Library of Queensland. Retrieved April 13, 2016.
^ ^a ^b ^c Haines, Betty (1999). Parchment. Leather Conservation Center. ISBN 9780946072057.
^ ^a ^b "INHERENT VICe: Materials". NEDCC. Northeast Document Conservation Center. Retrieved 23 April 2016.
^ Hingley, Mark (2001). "Success in the Treatment of Parchment and Vellum using a Suction Table". Journal of the Society of Archivists. 22 (1): 71–77. doi:10.1080/00379810120037513. S2CID 110087014.
^ Huxtable, Merryl (Autumn 2002). "Tethering the cow – Treatment and display of the Sackville Pedigree – a large 16th century heraldic parchment manuscript". Conservation Journal (42).
^ "Parchment". Library Preservation and Conservation. Cornell University.
^ Thompson, Jack. "Identifying Parchment". Conservation OnLine DistList.
^ Hansen, Lee & Sobel (1991). "THE EFFECTS OF RELATIVE HUMIDITY ON SOME PHYSICAL PROPERTIES OF MODERN VELLUM". Journal of the American Institute for Conservation. 33 (3).
^ ^a ^b Norman, Daniel (October 1993). "The mounting of single leaf parchment & vellum objects for display and storage". Conservation Journal (9).
^ ^a ^b "Parchment". Preservation Self-Assessment Program. University of Illinois Libraries. Retrieved 23 April 2016.
^ ^a ^b ^c Maekawa, Shin (11 February 1999). Oxygen-Free Museum Cases (PDF). The Getty Institute. ISBN 0-89236-529-3.
^ Kaplan & Ludwig. "Efficacy of Various Drying Methods". Archives.gov. National Archives and Records Administration. Retrieved 20 April 2016.
^ Quandt, Abigail (1996). "Recent Developments in the Conservation of Parchment Manuscripts". The Book and Paper Group Annual. 15. Retrieved 15 April 2016.
^ Garside & Walker (2015). "The Formation of Microenvironments in Polyester Enclosures". Journal of Conservation and Museum Studies. 13 (1). doi:10.5334/jcms.1021223.
^ "Code of Ethics and Guidelines for Practice".
^ Abdel-Maksoud, Gomaa; Emam, Hisham; Ragab, Nahla Mahmoud (2020). "From Traditional to Laser Cleaning Techniques of Parchment Manuscripts: A Review" (PDF). Advanced Research in Conservation Science. 1: 52–76. doi:10.21608/arcs.2020.111216. S2CID 237460068.
^ Vinas (1988). Traditional restoration techniques: a RAMP study. Paris: UNESCO.
^ Vest, Marie (Spring 2002). "Critical evaluation of laser cleaning of parchment documents". Conservation Journal. 40.
^ Woods, Chris (1995). "Conservation Treatments for Parchment Documents". Journal of the Society of Archivists. 16 (2): 221–239. doi:10.1080/00379819509511780.
^ Wikarski, Eyb-Green & Baatz (2015). "Filling in Losses in Parchment Bound Volumes – Part I: Assessment of Parchment and Paper Fibres in Reconstituted Parchment" (PDF). Restaurator. 36 (1): 25–46.
^ ^a ^b Pappalardo, Joe (July 3, 2020). "The Science of Saving the Declaration of Independence". Popular Mechanics. Archived from the original on July 17, 2018. Retrieved November 6, 2022.
^ ^a ^b Ritzenthaler, Mary Lynn; Nicholson, Catherine (2003). "A New Era Begins for the Charters of Freedom". National Archives. Archived from the original on December 26, 2005. Retrieved November 6, 2022.
^ ^a ^b "Saving the Charters of Freedom". The Washington Times. July 4, 2002. Archived from the original on November 7, 2022. Retrieved November 6, 2022.
^ "Declaration and Constitution: Travels of the Charters of Freedom". Brewminate. March 1, 2021. Archived from the original on March 1, 2021. Retrieved November 6, 2022.
^ Duffy, Christina. "Revealing the secrets of the burnt Magna Carta". British Library. Archived from the original on 18 June 2016. Retrieved 15 April 2016.

Sources

Quandt, Abigail B. (1996) Recent Developments in the Conservation of Parchment Manuscripts, The American Institute for Conservation Book and Paper Group Annual, http://aic.stanford.edu/sg/bpg/annual/v15/bp15-14.html
Hansen, Eric F., Lee, Steve N., Sobel, Harry. (1992) The Effects of Relative Humidity on Some Physical Properties of Modern Vellum: Implications for the Optimum Relative Humidity for the Display and Storage of Parchment. Journal of the American Institute for Conservation, Vol. 31, No. 3, pp. 325–342.
Reed, Ronald. (1975) The Nature and Making of Parchment. United Kingdom, Leeds; Lemete Press.

[1] Whymark, Francesca. "Is not parchment made of sheepskins? Ay, my lord, and of calfskins too..." British Library Collection Care Blog.

[18_Parchment_Treatments-2] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j ^k ^l "Parchment Treatments" (PDF). Conservation OnLine. Foundation of the American Institute for Conservation.

[3] "Caring for your collections: Parchment documents" (PDF). State Library of Queensland. Retrieved April 13, 2016.

[Betty_Haines-4] Haines, Betty (1999). Parchment. Leather Conservation Center. ISBN 9780946072057.

[NEDCC-5] "INHERENT VICe: Materials". NEDCC. Northeast Document Conservation Center. Retrieved 23 April 2016.

[6] Hingley, Mark (2001). "Success in the Treatment of Parchment and Vellum using a Suction Table". Journal of the Society of Archivists. 22 (1): 71–77. doi:10.1080/00379810120037513. S2CID 110087014.

[Sackville_manuscript-7] Huxtable, Merryl (Autumn 2002). "Tethering the cow – Treatment and display of the Sackville Pedigree – a large 16th century heraldic parchment manuscript". Conservation Journal (42).

[8] "Parchment". Library Preservation and Conservation. Cornell University.

[9] Thompson, Jack. "Identifying Parchment". Conservation OnLine DistList.

[10] Hansen, Lee & Sobel (1991). "THE EFFECTS OF RELATIVE HUMIDITY ON SOME PHYSICAL PROPERTIES OF MODERN VELLUM". Journal of the American Institute for Conservation. 33 (3).

[Single_leaf_parchment-11] Norman, Daniel (October 1993). "The mounting of single leaf parchment & vellum objects for display and storage". Conservation Journal (9).

[PSAP-12] "Parchment". Preservation Self-Assessment Program. University of Illinois Libraries. Retrieved 23 April 2016.

[Oxygen-Free-13] Maekawa, Shin (11 February 1999). Oxygen-Free Museum Cases (PDF). The Getty Institute. ISBN 0-89236-529-3.

[Drying_methods_-_NARA-14] Kaplan & Ludwig. "Efficacy of Various Drying Methods". Archives.gov. National Archives and Records Administration. Retrieved 20 April 2016.

[Quandt-15] Quandt, Abigail (1996). "Recent Developments in the Conservation of Parchment Manuscripts". The Book and Paper Group Annual. 15. Retrieved 15 April 2016.

[Garside_Microenvironments-16] Garside & Walker (2015). "The Formation of Microenvironments in Polyester Enclosures". Journal of Conservation and Museum Studies. 13 (1). doi:10.5334/jcms.1021223.

[17] "Code of Ethics and Guidelines for Practice".

[18] Abdel-Maksoud, Gomaa; Emam, Hisham; Ragab, Nahla Mahmoud (2020). "From Traditional to Laser Cleaning Techniques of Parchment Manuscripts: A Review" (PDF). Advanced Research in Conservation Science. 1: 52–76. doi:10.21608/arcs.2020.111216. S2CID 237460068.

[RAMP_Study-19] Vinas (1988). Traditional restoration techniques: a RAMP study. Paris: UNESCO.

[Laser_cleaning_Vest-20] Vest, Marie (Spring 2002). "Critical evaluation of laser cleaning of parchment documents". Conservation Journal. 40.

[woods1995-21] Woods, Chris (1995). "Conservation Treatments for Parchment Documents". Journal of the Society of Archivists. 16 (2): 221–239. doi:10.1080/00379819509511780.

[Reconstituted_parchment_fill-22] Wikarski, Eyb-Green & Baatz (2015). "Filling in Losses in Parchment Bound Volumes – Part I: Assessment of Parchment and Paper Fibres in Reconstituted Parchment" (PDF). Restaurator. 36 (1): 25–46.

[science-23] Pappalardo, Joe (July 3, 2020). "The Science of Saving the Declaration of Independence". Popular Mechanics. Archived from the original on July 17, 2018. Retrieved November 6, 2022.

[NARA_Charters-24] Ritzenthaler, Mary Lynn; Nicholson, Catherine (2003). "A New Era Begins for the Charters of Freedom". National Archives. Archived from the original on December 26, 2005. Retrieved November 6, 2022.

[saving-25] "Saving the Charters of Freedom". The Washington Times. July 4, 2002. Archived from the original on November 7, 2022. Retrieved November 6, 2022.

[26] "Declaration and Constitution: Travels of the Charters of Freedom". Brewminate. March 1, 2021. Archived from the original on March 1, 2021. Retrieved November 6, 2022.

[Magna_Carta_conservation-27] Duffy, Christina. "Revealing the secrets of the burnt Magna Carta". British Library. Archived from the original on 18 June 2016. Retrieved 15 April 2016.

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+{{Short description|Preservation of heritage collections}}
-The repair and mending of [[parchment]] has taken place for thousands of years. Methods from the earliest hand stitching of tears to today's use of modern equipment to mend and fill parchment show the importance that has been placed on its [[Preservation (library and archival science)|preservation]] and [[Art conservation|conservation]].
+[[Image:Permennter-1568.png|thumb|Illustration of a German parchmenter from 1568]]
+The '''conservation and restoration of parchment''' constitutes the care and treatment of [[parchment]] materials which have cultural and historical significance. Typically undertaken by professional [[Conservation and restoration of books, manuscripts, documents and ephemera|book and document conservators]], this process can include preventive measures which protect against future deterioration as well as specific treatments to alleviate changes already caused by agents of deterioration.
+==Parchment manufacturing and properties==
-==Flattening and crease removal==
+[[File:Perkament fabricage-516117.ogv|thumb|left|The making of parchment in the Netherlands]]
-Repairing curling and crease lines in parchment is generally achieved by raising its moisture content, though some modern techniques use little or no water.  Wetting parchment can cause damage, though it is sometimes unavoidable.
+[[Parchment]] is the skin of an animal, usually sheep, calf or goat, which has been dehaired, processed with a lime solution and stretched under tension. The dried material is a thin membrane which is most commonly used as a writing surface, but can also be used to make other items like [[bookbinding]]s and [[drumhead]]s. Throughout Europe, parchment was the primary writing substrate from its development in the 2nd century BCE through the [[Middle Ages]], though it is used through the present day for various official documents.<ref>{{cite web|last1=Whymark|first1=Francesca|title=Is not parchment made of sheepskins? Ay, my lord, and of calfskins too...|url=http://britishlibrary.typepad.co.uk/collectioncare/2013/09/parchment-conservation-lyte-geneaology.html|website=British Library Collection Care Blog}}</ref> Typically parchment made from calfskin is called [[vellum]], though the term can also be used to refer to very fine quality parchment made from the skins of other animals. For the purposes of conservation and restoration, the term parchment is used in reference to vellum objects, as the terms have been used interchangeably throughout time to refer to objects with the same conservation concerns.<ref name="18 Parchment Treatments">{{cite web|title=Parchment Treatments|url=http://cool.conservation-us.org/coolaic/sg/bpg/pcc/18_parchment.pdf|website=Conservation OnLine|publisher=Foundation of the American Institute for Conservation}}</ref>
+Parchment has unique structural qualities which differentiate it from paper-based materials. Typically, parchment is resistant to mechanical damage like tears or creasing, though it is easily susceptible to damage from mold and high temperatures.<ref name="18 Parchment Treatments" /> Parchment is also highly [[hygroscopic]] in nature, meaning that changes in [[relative humidity]] can cause irreversible variations to its structural makeup. <ref>{{cite web|title=Caring for your collections: Parchment documents|url=http://www.slq.qld.gov.au/__data/assets/pdf_file/0006/276234/Caring-for-your-collections-Parchment-documents.pdf|website=State Library of Queensland|access-date=April 13, 2016}}</ref> These specific qualities dictate the conservation and restoration treatments required for parchment.
-If the entire piece of parchment needs to be flattened, one technique is to place the parchment into a controlled humidity chamber with a relative humidity of 95% or more.  According to Bety Haines', one important factor to monitor is to make sure the vapor has penetrated to the core uniformly, and at its own rate, and not just the surface of the parchment. Once this has happened, the use of tensioning with clips will allow creases to be eased.
+===Physical and chemical properties===
-If just a few creases need to be eased, 80% to 90% [[isopropyl alcohol]] may be applied to the creases directly. Heavier skins may need the higher water content. The Alcohol-Water mixture is [[azeotropic]], meaning both components will evaporate simultaneously.  The solution has a lower surface tension than water, which causes the fibers to suffer less shrinkage.<ref name=woods2006/> The solution can be applied with a cotton swab and then gently pulled flat by hand.
+Most skins used for parchment are 1–3&nbsp;mm in thickness before processing. Animal skin used for parchment all has the same basic structure, with slight variations due to the species, age and diet of the specific animal. Skin is composed of innumerable fibrils made up of the protein [[collagen]], which are held in bundles that interweave in a three dimensional manner through the skin.  The fibrous material is composed of many long chain molecules of collagen, which can react with certain environmental factors. One universal property of collagen is that it exhibits sudden shrinkage when heated in water, starting at {{Cvt|65|C}}. Prolonged exposure to alkali, like in parchment liming process, changes the amino acids, consequently dropping shrinkage temperatures as low as {{Cvt|55|C}}.<ref name="Betty Haines">{{cite book|last1=Haines|first1=Betty|title=Parchment|year=1999|publisher=Leather Conservation Center|isbn=9780946072057}}</ref>
+=== Manufacturing===
-The easiest and safest method to flatten parchment is to humidify and then dry and flatten it on the vacuum suction table rather than using the clips and tensioning frame.  Suction table flattening is widely employed in the United States.
+Once it is removed from the animal, the skin is temporarily preserved, either by drying or liberal application of salt, until it can be processed. The skin is then immersed in water for 48 hours, which cleans and rehydrates it. This step also removes the non-collagenous materials, like [[hyaluronic acid]], [[dermaten sulphate]] and [[plasma proteins]]. The skin is then soaked in a lime or [[alkali]] solution, known as the [[Liming (leather processing)|liming]] process.<ref name="Betty Haines" /> In the 19th century, chemicals were added to speed up the liming process, which resulted in weaker parchments. These added compounds sometimes reacted to produce gypsum, giving the parchment a characteristic gray hue.<ref name="NEDCC" /> The skin is then stretched in suspension on a frame, constricting it as it dries. This ensures even contraction across the entire parchment which ensures that it will remain flat when dried.<ref>{{cite journal|last1=Hingley|first1=Mark|title=Success in the Treatment of Parchment and Vellum using a Suction Table|journal=Journal of the Society of Archivists|date=2001|volume=22|issue=1|pages=71–77|doi=10.1080/00379810120037513|s2cid=110087014}}</ref> After being prepared, parchment is sometimes coated so that it is more receptive to pigment and ink. Historical coatings, which include chalk, egg whites and matte paint, must be taken into consideration as a meaningful part of the preservation and conservation plan.<ref name="18 Parchment Treatments" />
+The manufacturing process, which removes the skin's natural fats and oils, means that parchment is more reactive to moisture and relative humidity than other skin-based material. After being stretched, parchment has an inherent desire to revert to its original animal shape, especially if left unrestrained or exposed to repeated changes in relative humidity.<ref name="Sackville manuscript">{{cite journal|last1=Huxtable|first1=Merryl|title=Tethering the cow – Treatment and display of the Sackville Pedigree – a large 16th century heraldic parchment manuscript|journal=Conservation Journal|date=Autumn 2002|issue=42|url=http://www.vam.ac.uk/content/journals/conservation-journal/issue-42/tethering-the-cowtreatment-and-display-of-the-sackville-pedigreea-large-16th-century-heraldic-parchment-manuscript/}}</ref>
-A fully humidified parchment is placed on a suction table at low suction and then covered with polyester film strips of varying sizes.  Once the suction is turned up, the parchment is gently stretched and mainpulated until flat and then held in place with the polyester strips.  After the parchment is satisfactorily flattened overall, the polyester strips are removed and replaced with a blotter or [[Gore-Tex]] sheet for further drying and flattening.  After treatment on the suction table, the parchment is placed in a weighted blotter stack to further dry and flatten.
+===Identification===
-Another method of localized treatment involves the use of an [[ultrasonic humidifier]] to add humidification in a controlled area. During the process, tension is gradually placed on the edges of the parchment to release the creases and then it is dried under pressure between polyester web and thick wool felts.
+Parchment is usually positively identified by sight, sometimes with the assistance of a [[hand lens]] or [[microscope]]. Visible hair follicle pattern, veining, scars, bruises and sometimes fat deposits all help confirm the animal origin of the material. Additional light sources including [[ultraviolet]] lights, can make these properties more easily identifiable.<ref>{{cite web|title=Parchment|url=https://www.library.cornell.edu/preservation/librarypreservation/mee/preservation/parchment.html|website=Library Preservation and Conservation|publisher=Cornell University}}</ref>
+Sometimes visual examination is not sufficient to distinguish parchment from certain types of highly [[calender]]ed papers. Misidentification of these materials can lead to inappropriate preservation methods or conservation treatments.<ref name="18 Parchment Treatments" /> Analytical testing, which involves removing a small piece of parchment, can be done by or under the supervision of a professional conservator-restorer to ensure positive identification. One type of analytical testing involves examining the parchment specimen under a [[light microscope]] or [[scanning electron microscopy]]. A simple flame test can also be done on the parchment specimen; true parchment will emit the meaty smell of burned protein, while other look-alike materials will smell like paper or wood.<ref>{{cite web|last1=Thompson|first1=Jack|title=Identifying Parchment|url=http://cool.conservation-us.org/byform/mailing-lists/cdl/2002/0610.html|website=Conservation OnLine DistList}}</ref>
-==Cleaning==
-Any necessary cleaning is done before using any techniques that raise the parchment's moisture content. Humidification can cause the dirt to become ingrained in the parchment, potentially making stains irreversible.
+==Agents of deterioration==
-Before cleaning, it is imperative that the conservator assess the condition of the media on the surface of the parchment.  If insecure media such as pen and ink is noted, consolidation is required before surface cleaning.   Consolidation is undertaken locally by introducing various dilute adhesives like isinglass, gelatin or parchment size through brush application or by the use of an ultrasonic humidifcation appratus.  The quality of parchment size varies widely so the use of laboratory grade gelatin is preferable.  Subsequent humidification treatment of the parchment is also thought to reestablish adhesive bonds between the media and the parchment.
+*'''Relative humidity changes'''<ref>{{cite journal|last1=Hansen, Lee & Sobel|title=THE EFFECTS OF RELATIVE HUMIDITY ON SOME PHYSICAL PROPERTIES OF MODERN VELLUM|journal=Journal of the American Institute for Conservation|date=1991|volume=33|issue=3|url=http://cool.conservation-us.org/jaic/articles/jaic31-03-005.html}}</ref>
-Surface cleaning of parchment is typically completed using white vinyl erasers (solid and grated) and confined to areas where no media is present.
+Changes in [[relative humidity]] can cause parchment to change shape, especially if movement is restrained by a frame or mount at certain parts of the object, which leads to uneven distortion. This distortion can result in cockling and destabilization of any pigments affixed to the parchment.<ref name="Single leaf parchment">{{cite journal|last1=Norman|first1=Daniel|title=The mounting of single leaf parchment & vellum objects for display and storage|journal=Conservation Journal|date=October 1993|issue=9|url=http://www.vam.ac.uk/content/journals/conservation-journal/issue-09/the-mounting-of-single-leaf-parchment-and-vellum-objects-for-display-and-storage/}}</ref> Low humidity levels can cause parchment to [[Desiccation|desiccate]].<ref name="PSAP" />
+*'''Water and excessive moisture'''
+Direct water contact and excessive moisture in the environment can cause structural problems for parchment including: expansion of object; discoloration; alteration of surface coatings; gelatinization of skin; and realignment of fibers.<ref name="18 Parchment Treatments" />
+*'''Oxygen'''
+Atmospheric oxygen reacts with the chemical composition of parchment, which subsequently changes the physical properties of the object over time.<ref name="Oxygen-Free" />
+*'''Mold'''
+Mold is a probable consequence of water damage to parchment, especially when the object is not dried within 48 hours of the initial contact with water.<ref name="Drying methods - NARA">{{cite web|last1=Kaplan & Ludwig|title=Efficacy of Various Drying Methods|url=https://www.archives.gov/preservation/conservation/drying-methods-01.html|website=Archives.gov|publisher=National Archives and Records Administration|access-date=20 April 2016}}</ref>
+*'''Heat:'''
+Heat in excess of the ideal storage conditions can cause damage to collagen structure, irreversible contraction and alteration of surface materials in parchment objects.<ref name="18 Parchment Treatments" />
+*'''Light exposure'''
+Lower wavelength and [[ultraviolet]] light lead to degradation of the collagen structure and photodiscoloration, usually causing yellowing of parchment.<ref name="Betty Haines" /> Parchment exposed to UV light can also have a photochemical reaction causing it to become brittle.<ref name="NEDCC">{{cite web|title=INHERENT VICe: Materials|url=https://www.nedcc.org/preservation101/session-4/2inherent-vice-materials#parchment|website=NEDCC|publisher=Northeast Document Conservation Center|access-date=23 April 2016}}</ref>
+*'''Flaking and friability'''
+Consolidation of media on parchment, such as those found in [[Conservation and restoration of illuminated manuscripts#inks and pigments|illuminated manuscripts]], is compromised by the instability of the parchment substrate. Excessive flexing or chemical changes in the parchment can lead to loss of pigment and text.<ref name="Quandt">{{cite journal|last1=Quandt|first1=Abigail|title=Recent Developments in the Conservation of Parchment Manuscripts|journal=The Book and Paper Group Annual|date=1996|volume=15|url=http://cool.conservation-us.org/coolaic/sg/bpg/annual/v15/bp15-14.html|access-date=15 April 2016}}</ref>
+*'''Poor storage'''
+Parchment which has been adhered to a rigid mount for storage or display is unable to expand and contract, as its natural tendency. This poor storage technique can lead to tears, perforations and loss. Parchment stored in an unregulated and inconsistent environment is more susceptible to damage.<ref name="PSAP">{{cite web|title=Parchment|url=https://psap.library.illinois.edu/format-id-guide/parchment|website=Preservation Self-Assessment Program|publisher=University of Illinois Libraries|access-date=23 April 2016}}</ref>
+==Storage and preventive care==
-==Mending tears==
+Proper storage environments can help ward off structural, chemical and environmental changes which affects the long-term preservation of parchment. Storage factors must take into account the factors of the particular parchment object, including its condition, age, storage history and plans for use. [[Conservation and restoration of illuminated manuscripts|Illuminated manuscripts]] and composite parchment objects, which may include [[Seal (emblem)|seals]] and ribbons, may have additional storage needs.<ref name="18 Parchment Treatments" /> A consistent storage environment is crucial for the long-term stability of parchment, which is especially vulnerable to changes in humidity, temperature and other environmental factors.<ref name="Single leaf parchment" />
-Early mending techniques were often as basic as hand-stitching the tear together. Modern techniques for repairing splits and tears use adhesive-coated tissues and animal membranes.
+Microenvironments are less expensive ways to provide consistent storage environments for parchment if the external storage conditions are not ideal. Moisture sensitive parchments can be stored in a [[Plexiglas]] sandwich by inserting the matted parchment between two sheets of acrylic and taping off all sides. Parchment can also be stored in envelopes constructed out of [[polyester]] sheets.<ref name="Garside Microenvironments">{{cite journal|last1=Garside & Walker|title=The Formation of Microenvironments in Polyester Enclosures|journal=Journal of Conservation and Museum Studies|year=2015|volume=13|issue=1|doi=10.5334/jcms.1021223|doi-access=free }}</ref>
-The adhesive chosen for parchment mending is important so as not to further damage the item being repaired. To minimize damage, repairs are performed using adhesives with the least amount of moisture required for the specific task.
+For the long-term preservation of organic material like parchment, the ideal temperature range is {{Cvt|10-15|C}} with a [[relative humidity]] level of 30–50%. The ideal storage and display environment is oxygen-free, as oxygen prevalence has been shown to react with collagen over time, leading to increased brittleness of parchment. Oxygen-free storage and display cases are filled with [[inert gas]] as well as a chemical substance that reacts as an absorber if any stray oxygen leaks into the encasement.<ref name="Oxygen-Free">{{cite book|last1=Maekawa|first1=Shin|title=Oxygen-Free Museum Cases|date=11 February 1999|publisher=The Getty Institute|isbn=0-89236-529-3|url=http://www.getty.edu/conservation/publications_resources/pdf_publications/pdf/oxygenfree.pdf}}</ref>
-Parchment is mostly collagen, and collagen becomes gelatin when boiled in water.  A gelatin solution (although pure, without lime) can be used for parchment repair. Gelatin is somewhat hydrophilic and has similar aging characteristics to parchment. The solution used is typically 12% powdered [[gelatin]] added to 88% water and warmed to 80 degrees Celsius while stirring continuously.<ref name=woods1995>{{cite journal|doi=10.1080/00379819509511780|author=Woods, Chris|year=1995|title= Conservation Treatments for Parchment Documents|journal=Journal of the Society of Archivists|volume=16|issue =2|pages=221–239}}</ref> Anthony Cains recommends for every 100 mL of solution, adding three drops of 2% aqueous [[sorbitol]] as a [[humectant]], and two drops of an aqueous solution of 1% [[acetic acid]] to aid the effectiveness of the adhesive.<ref name=cains>{{cite journal|author=Cains, A.|year=1983|journal=The Paper Conservator|volume= 7|pages=16–17|title= Repair Treatments for Vellum Manuscripts|doi=10.1080/03094227.1982.9638444}}</ref> Earlier techniques used [[honey]] as a humectant.
+==Ethical concerns of conservation==
-Before use, the solution is heated to 100 degrees C for 5–10 minutes which to give it a higher degree of tackiness.  Prior to application to the parchment, the solution must be cooled but still liquid. The adhesive can turn the parchment transparent if too warm, so the adhesive is applied to the repair material and not directly to the parchment.
+The [[American Institute for Conservation]]'s Code of Ethics and Guidelines for Practice set forth the conduct for conservation and restoration treatments of parchment objects.<ref>{{Cite web|url=https://www.culturalheritage.org/about-conservation/code-of-ethics|title=Code of Ethics and Guidelines for Practice}}</ref> The hazards of specific treatments need to be weighed against the benefits, as many traditional liquid-based conservation techniques can pose risks to parchment.<ref>{{Cite journal|last1=Abdel-Maksoud|first1=Gomaa|last2=Emam|first2=Hisham|last3=Ragab|first3=Nahla Mahmoud|date=2020|title=From Traditional to Laser Cleaning Techniques of Parchment Manuscripts: A Review|url=https://arcs.journals.ekb.eg/article_111216_b4d2045b83d9145399d8975111c59a5b.pdf|journal=Advanced Research in Conservation Science|volume=1|pages=52–76|doi=10.21608/arcs.2020.111216|s2cid=237460068|doi-access=free}}</ref>
+==Conservation treatments==
-Suggestions for the actual repair materials vary. Many recommend the use of [[Goldbeater's skin]] which is the outer membrane of [[calf]]'s [[intestine]]. Others use light-weight, long-fiber [[Japanese tissue]].
+===Removal of previous restorations===
+Previous repairs and conservation treatments are removed if it is determined that the parchment is in good condition and that the repair is not of historic importance to the parchment. Dried out patches are removed via cleaning and humidification techniques. Parchment objects that have been attached to mounts are removed with a sharpened lifting tool and a small amount of moisture. Previous laminations, like [[Goldbeater's skin]] and Mipofolie, can sometimes be removed with solvents and mechanical techniques, though this removal technique can risk additional damage to the original parchment.<ref name="18 Parchment Treatments" />
+===Cleaning===
-When it is acceptable for a minimal amount of water to come in contact with the parchment, it is possible to use an alternative technique that uses [[Isinglass]].  Isinglass is a film known for its adhesive strength made by soaking and then cooking a dried [[Russian sturgeon]] bladder at low temperature. In the technique, as described by Tatyana Petukhove, a paper conservator at [[Cornell University]] Library, the isinglass is reactivated with ethanol and water.  Then honey or a few drops of glycerin are added before applying the material to the parchment.
+Surface cleaning of parchment has been developed after methods used for cleaning paper, with a few key differences related to the structural and chemical properties of parchment.  For the most part, chemical treatments are ineffective and some, like hypochlorites and [[methyl bromide]], can [[Denaturation (biochemistry)|denaturalize]] parchment. Prior to cleaning, any flaking or vulnerable media is [[Conservation_and_restoration_of_illuminated_manuscripts#Consolidation|consolidated]] to ensure it does not detach from the parchment substrate. Consolidation of parchment media is undertaken by applying various dilute adhesives like isinglass, gelatin or parchment size through brush application or by the use of an ultrasonic humidification apparatus.
+If their presence is determined upon examination, insects and pests are eliminated and the parchment disinfected. An appropriate round of [[fumigation]] in an [[autoclave]] is used to remove pests and sterilize the object. Dry and wet cleaning techniques can both be used effectively on parchment objects. Mechanical cleaning using erasers and other abrasive tools is used to remove mildew and dirt. Surface cleaning of parchment is typically completed using white vinyl erasers (solid and grated) and confined to areas where no media is present. Water baths, which sometimes use neutral detergents or alcohol as additives, can be used to clean as well as prepare the parchment for stretching as part of the conservation process.<ref name="RAMP Study">{{cite book|last1=Vinas|title=Traditional restoration techniques: a RAMP study|date=1988|publisher=UNESCO|location=Paris|url=http://www.unesco.org/webworld/ramp/html/r8817e/r8817e09.htm}}</ref> Another wet cleaning method, which is especially useful for removing mold and mildew, uses a cotton swab covered in fluid, usually [[denatured alcohol]], ethanol or saliva. [[Laser]] cleaning may provide a non-contact cleaning process, though conservation labs throughout Europe still mostly use traditional wet and dry cleaning methods for parchment.<ref name="Laser cleaning Vest">{{cite journal|last1=Vest|first1=Marie|title=Critical evaluation of laser cleaning of parchment documents|journal=Conservation Journal|date=Spring 2002|volume=40|url=http://www.vam.ac.uk/content/journals/conservation-journal/issue-40/critical-evaluation-of-laser-cleaning-of-parchment-documents/}}</ref>
-Adhesives used to repair parchment in the United States includes isinglass, laboratory grade gelatin, wheat starch paste, aquazol, and in some instances, PVA. Mixtures of the wheat starch paste and other listed adhesives are also recommended.
+===Humidification===
-==Infilling of Losses==
+Humidification is a parchment conservation treatment which involves the controlled and monitored increase in relative humidity. Humidified parchments are more flexible, which will allow for corrections to distortions like cockling, puckering and changes in original size. Some methods of humidification are: humidification chambers: moisture chambers with ultrasonic [[humidifier]], moisture chambers with steam/ultrasonic mist; and application of alcohol and water. Localized humidification is sometimes used to treat specific folds or creases in parchment objects.<ref name="18 Parchment Treatments" />
-Repairing ragged edged holes or missing areas is more extensive. This process is called infilling and uses a pulp mixture to fill in the missing areas.
+===Flattening, tensioning and drying===
-In a treatment used in 1985 by Per Laursen, a Dutch conservator, "the parchment ...is laid on a paper [[suction table]] and a dry powder, made from unprocessed animal hide, is applied to the area of loss with a spray apparatus. The excess hide powder is brushed away from the surrounding area and the fill is lightly sprayed with [[ethanol]] and smoothed in place through a piece of [[polyethylene]]. A [[casein]]-based adhesive....is applied with a brush to the dry powder fill, which is left to dry for about 10 minutes."
+After humidification, drying techniques are necessary to ensure that the parchment lays flat and does not suffer additional moisture-related issues. The specific method is dependent on the condition of the object, as well as the humidification process utilized. Some of the most common methods include:
+*Drying and flattening under pressure, often pressed between two absorbent surfaces
+*Tensioning at the edges, where the parchment is constricted at the edges with weights or clips. This techniques most closely reflects parchment's original manufacturing process.
+*Stretch drying on [[Polyethylene terephthalate|Terylene]]
+*Vacuum suction table flattening<ref name="18 Parchment Treatments" />
+Localized creases are eased with a solution of 80% to 90% [[isopropyl alcohol]] and water, which is applied to the creases directly with a cotton swab and then gently pulled flat by hand. The alcohol–water mixture is [[azeotropic]], meaning both components evaporate simultaneously. The solution has a lower surface tension than just water, which causes the fibers to suffer less shrinkage.<ref name=woods1995>{{cite journal|doi=10.1080/00379819509511780|author=Woods, Chris|year=1995|title= Conservation Treatments for Parchment Documents|journal=Journal of the Society of Archivists|volume=16|issue =2|pages=221–239}}</ref>
-The parchment is then dried between [[polyester]] web with blotters under pressure for 12 hours.  This particular technique has some issues.  One problem is the fill is not always even in thickness.  Another problem is that large areas have trouble adhering and need to be supported on both sides with goldbeater's skin.
+===Mending and in-filling losses===
-An alternative technique was developed in Hungary.  It uses a pulp made from untanned animal hide ground up with Japanese paper (for color) and a [[sulfite]]-processed paper pulp. Parchment size, made from wine vinegar, [[hydroxyethyl methylcellulose]], [[ethanol]], isopropyl alcohol, and a [[fungicide]] is added to the pulp. The parchment is placed on a [[suction table]] with a [[light box]] underneath and the pulp applied with an eye dropper. The fill is applied to both sides of the parchment if needed.
+Sewing tears is not recommended as a conservation treatment, unless it is replacing a sewn portion original to the object. Correcting non-original splits, tears, perforations and losses in parchment requires careful consideration of its specific condition. For losses that do not require much support, transparent membranes, such as fish skin or sausage casing, are placed over the damaged area with an adhesive. Infill materials, including new parchment, reconstituted parchment and [[Washi|Japanese paper]], are used to repair losses requiring greater structural support. All infill materials have some conservation concerns, as they will react differently  to environmental factors than the original parchment.
+*New parchment: It is difficult to match the infill material to the original parchment type in terms of animal, thickness and appearance. Modern parchments that appear visually similar also respond differently to humidity fluctuations, causing potential problems after the conservation treatment. Parchment infills are matched by thinning them to the appropriate size and [[Bevel|bevelling]] the original parchment before the repair.
+*Japanese paper: Paper is dissimilar to parchment in both appearance and behavior, which can pose the future issue of storing an object with composite materials. Paper infills can be toned with watercolor or [[acrylic paints]] to better match the original parchment appearance. Acrylic-toned papers are treated with various adhesives such as B-72, Aquazol, or PVA to mimic the translucency of the surrounding parchment. Varying layers of application are used to best approximate the thickness and condition of the specific original parchment.<ref name="18 Parchment Treatments" />
+*Reconstituted parchment: Collagen fibers and dry [[cellulose]] materials are mixed together with liquid ingredients to create a [[Pulp (paper)|pulp]]-like substance. This material is applied to the original parchment in a process similar to [[leafcasting]] paper.<ref name="Reconstituted parchment fill">{{cite journal|last1=Wikarski, Eyb-Green & Baatz|title=Filling in Losses in Parchment Bound Volumes – Part I: Assessment of Parchment and Paper Fibres in Reconstituted Parchment|journal=Restaurator|date=2015|volume=36|issue=1|pages=25–46|url=http://www.degruyter.com/dg/viewarticle.fullcontentlink:pdfeventlink/$002fj$002frest.2015.36.issue-1$002fres-2014-0103$002fres-2014-0103.pdf?format=INT&t:ac=j$002frest.2015.36.issue-1$002fres-2014-0103$002fres-2014-0103.xml}}</ref>
+===Disaster recovery===
-Another fill method applies the pulp to a piece of [[silk]] cloth.  The prepared pulp is later lifted off and pressed gently into place on the parchment. This method introduces less moisture to the parchment.
+Parchment which has been accidentally exposed to excess moisture or water is extremely susceptible to mold, mechanical damage and irreversible dimensional changes. Emergencies often affect large quantities of objects, therefore the mass treatment of objects usually includes freezing or [[freeze-drying]] as the first step. As time permits, parchment object are then thawed and dried using more traditional measures.<ref name="18 Parchment Treatments" />
+==Case studies==
-Japanese paper inserts are also used by conservators to fill losses in parchment.  Acrylic-toned Japanese papers can be treated with various adhesives such as B-72, Aquazol, or PVA to mimic the translucency of the surrounding parchment.
+===Charters of Freedom===
+The United States [[United States Declaration of Independence|Declaration of Independence]], [[United States Constitution|Constitution]] and the [[United States Bill of Rights|Bill of Rights]], collectively known as the Charters of Freedom, were housed in metal and glass encasements, filled with [[helium]] gas, from 1952 to 2001.<ref name="science">{{cite web |url=https://www.popularmechanics.com/technology/a22025447/declaration-of-independence-science/ |title=The Science of Saving the Declaration of Independence |last=Pappalardo |first=Joe |date=July 3, 2020 |website=Popular Mechanics |access-date=November 6, 2022 |archive-url=https://web.archive.org/web/20180717203752/https://www.popularmechanics.com/technology/a22025447/declaration-of-independence-science/ |archive-date=July 17, 2018}}</ref><ref name="NARA Charters">{{cite web |url=https://www.archives.gov/publications/prologue/2003/fall/charters-new-era.html |title=A New Era Begins for the Charters of Freedom |last1=Ritzenthaler |first1=Mary Lynn |last2=Nicholson |first2=Catherine |date=2003 |publisher=National Archives |access-date=November 6, 2022 |archive-url=https://web.archive.org/web/20051226050917/https://www.archives.gov/publications/prologue/2003/fall/charters-new-era.html |archive-date=December 26, 2005}}</ref><ref name="saving" /> In 1951, the [[National Bureau of Standards]] reported that an inert gas environment would be the best means of preserving the Charters of Freedom.<ref name="Oxygen-Free" /> In 1982, the [[National Archives and Records Administration]] partnered with the [[Jet Propulsion Laboratory]] on a nine-year project which determined that the encasement glass was deteriorating. Upon the issuing of this report, it was decided that new encasements and conservation treatments were needed for the long-term preservation of the Charters of Freedom. The documents were thoroughly examined for signs of deterioration and past restorations, all of which were thoroughly documented in condition reports.<ref>{{cite web |url=https://brewminate.com/declaration-and-constitution-travels-of-the-charters-of-freedom/ |title=Declaration and Constitution: Travels of the Charters of Freedom |date=March 1, 2021 |website=Brewminate |access-date=November 6, 2022 |archive-url=https://web.archive.org/web/20210301191754/https://brewminate.com/declaration-and-constitution-travels-of-the-charters-of-freedom/ |archive-date=March 1, 2021}}</ref>
+The first step of treatment stabilized the ink of the text using a gelatin adhesive. The dirt and grime were then cleaned from the parchments, though original intentional marks were left alone. The Constitution and the Bill of Rights were then humidified and dried under tension to flatten the parchments. The Declaration of Independence, which has been damaged by frequent handling and exposure, was not humidified because of its increased moisture sensitivity.<ref name="science" /> All the parchments were then installed into new titanium and aluminum encasements, developed by the [[National Institute of Standards and Technology]], which are filled with inert [[argon]] gas.<ref name="saving">{{cite web |url=https://www.washingtontimes.com/news/2002/jul/4/20020704-033114-2710r/ |title=Saving the Charters of Freedom |date=July 4, 2002 |website=The Washington Times |access-date=November 6, 2022 |archive-url=https://web.archive.org/web/20221107013835/https://www.washingtontimes.com/news/2002/jul/4/20020704-033114-2710r/ |archive-date=November 7, 2022}}</ref> The current environmental conditions of the Charters of Freedom encasements is monitored by scientists and conservators for signs of possible deterioration agents.<ref name="NARA Charters" />
-== Problems with past conservation methods ==
+===Canterbury Magna Carta===
-Parchment is very durable and many pieces have lasted hundreds of years, often with little help. Sometimes the "help" from conservation methods in the past has caused more damage than good.
+In 1731, one of four surviving copies of the 1215 [[Magna Carta]], known as the Canterbury Magna Carta, was partially damaged in a fire at its temporary storage location at [[Ashburnham House]]. Damage included shrinkage and discoloration of the parchment substrate, though the ink text was still legible. In the 1830s, [[British Museum]] staff attempted a restoration, using chemicals to treat the parchment and unintentionally rendering the text illegible.
+In 2014, the [[British Library]] undertook a [[Multispectral image|multispectral imaging]] project to determine if the text on the damaged document could be recovered. Analysis under [[ultraviolet]] light allowed scientists and conservators to see text that was invisible to the naked eye. This new technology allows the document to be used for continued research purposes, despite the previous botched restoration.<ref name="Magna Carta conservation">{{cite web|last1=Duffy|first1=Christina|title=Revealing the secrets of the burnt Magna Carta|url=http://www.bl.uk/magna-carta/articles/revealing-the-secrets-of-the-burnt-magna-carta|website=British Library|access-date=15 April 2016|archive-date=18 June 2016|archive-url=https://web.archive.org/web/20160618145117/http://www.bl.uk/magna-carta/articles/revealing-the-secrets-of-the-burnt-magna-carta|url-status=dead}}</ref>
-Despite the damage water can cause to parchment, water has often been used to flatten parchment to make its information more accessible and to facilitate further repairs, such as mending with [[starch]] paste.
-Starch paste can also cause problems.  Starch paste is a low-tack [[glucose]]-based [[carbohydrate]]. In repairs using starch paste, the paste moistens the parchment, but typically, just the area where the paste is applied becomes moistened.  In this case, as the paste dries, there is a humidity imbalance in the parchment that results in a distortion around the paste. This distortion irreversibly affects the skin structure.
-Instead of using starch paste, it would be better to use something [[protein]] based and hydrophilic.  According to Woods, "starch cannot be considered compatible with parchment. My understanding of compatibility is the use of like with like...The principle is that if genuine, damage-free reversibility is not possible, it may be better to use the same material as that of which the conserved item is constituted, since its aging characteristics are known to be sympathetic."<ref name=woods2006>Woods Chris, [http://books.google.com/books?id=YCByAK2EVJgC&pg=PA200 ''The Conservation of Parchment''], chapter 20, pp. 200–224 in ''Conservation of Leather & Related Materials'', Kite, M. and Thomson, R. (eds.), Butterworth-Heinmann, Oxford 2006 ISBN 113641522X.</ref>
-Starch-based adhesives to repair parchment are used by many conservators in the United States and Canada.
-== Parchment preservation ethics ==
-There are many ethical issues when working with parchment manuscripts. One of these issues is whether or not to add any toning to pulp to color it, or to use colored Japanese papers for mending. The concern is that the repair should be easily recognizable as a repair and not try to look like the original parchment. Some conservators feel though that some color is desirable, as it reduces the brightness of the new materials.
 == References ==
@@ Line 70: / Line 97: @@
 {{reflist}}
-=== Bibliography ===
+=== Sources ===
-* Abt, Jeffrey; Fusco, Margaret. (1989) A Byzantine Scholar's Letter on the Preparation of Manuscript Vellum, ''Journal of the American Institute for Conservation'', Vol. 28, No. 2, pp.&nbsp;61–66.
+* Quandt, Abigail B. (1996) Recent Developments in the Conservation of Parchment Manuscripts, ''The American Institute for Conservation Book and Paper Group Annual'', http://aic.stanford.edu/sg/bpg/annual/v15/bp15-14.html
-* Quandt, Abigail B. (1996) Recent Developments in the Conservation of Parchment Manuscripts, ''The American Institute for Conservation Book and Parer Group Annual'', http://aic.stanford.edu/sg/bpg/annual/v15/bp15-14.html
-* Wachter, Otto. (1962) The Restoration of the "Vienna Dioscorides", ''Studies in Conservation'', Vol. 7, No. 1, pp.&nbsp;22–26.
 * Hansen, Eric F., Lee, Steve N., Sobel, Harry. (1992) The Effects of Relative Humidity on Some Physical Properties of Modern Vellum: Implications for the Optimum Relative Humidity for the Display and Storage of Parchment. ''Journal of the American Institute for Conservation'', Vol. 31, No. 3, pp.&nbsp;325–342.
 * Reed, Ronald. (1975) The Nature and Making of Parchment. United Kingdom, Leeds; Lemete Press.
-== External Links ==
-*[http://blog.nyhistory.org/parchment/ Preservation of 18th Century Parchment | "From the Stacks" at New-York Historical Society]
+{{Cultural Conservation-Restoration |state=expanded}}
-{{Paper}}
-[[Category:Manuscripts]]
+[[Category:Conservation and restoration of cultural heritage]]
-[[Category:Preservation (library and archival science)]]
+[[Category:Leather]]
-[[Category:Maintenance]]
-[[Category:Paper]]

v t e Cultural heritage and historic preservation
Topics and issues	Agents of deterioration Archival processing Archaeological science Archaeology Archive Bioarchaeology Book Calendar (archives) Conservation and restoration of cultural property Conservation and restoration of immovable cultural property Conservation and restoration of movable cultural property Conservation science (cultural property) Collecting Collection (museum) Collection catalog Collections maintenance Collections management Collections management system Cultural heritage Cultural heritage management Cultural property Cultural property documentation Cultural property exhibition Cultural property imaging Cultural property storage Cultural resources management Database preservation Deaccessioning (museum) Digital library Digital photograph restoration Digital preservation Disaster preparedness (cultural property) Film preservation Finding aid Fonds Found in collection Heritage asset Heritage science Inherent vice Intangible cultural heritage Integrated pest management (cultural property) Inventory (library and archive) Inventory (museum) Media preservation Midden Mold control and prevention (library and archive) Museum Optical media preservation Preservation (library and archive) Preservation metadata Preservation survey Provenance Repatriation Ruins Sustainable preservation Treasure Web archiving
Roles and expertise	Archivist Art dealer Art handler Auctioneer Collection manager Conservator-restorer Conservation scientist Conservation technician Curator Exhibition designer Mount maker Objects conservator Paintings conservator Photograph conservator Preservationist Registrar (cultural property) Textile conservator
Methods and techniques	Aging (artwork) Anastylosis Arrested decay Cradling (paintings) Cultural property radiography Detachment of wall paintings Desmet method Display case Digital repository audit method based on risk assessment Historic paint analysis Inpainting Kintsugi Leafcasting Lining of paintings Mass deacidification Overpainting Paleo-inspiration Paper splitting Reconstruction (architecture) Rissverklebung Textile stabilization Transfer of panel paintings UVC-based preservation VisualAudio
Conservation and restoration of immovable cultural property by item type	Archaeological sites Frescos Heritage railways Historic gardens Outdoor artworks Outdoor bronze objects Outdoor murals
Conservation and restoration of movable cultural property by item type	Aircraft Ancient Greek pottery Bone, horn, and antler objects Books, manuscripts, documents and ephemera Ceramic objects Clocks Copper-based objects Feathers Film Flags and banners Fur objects Glass objects Herbaria Human remains Illuminated manuscripts Insect specimens Iron and steel objects Ivory objects Judaica Lacquerware Leather objects Lighthouses Metals Musical instruments Neon objects New media art Paintings Painting frames Panel paintings Papyrus Parchment Performance art Photographs Photographic plates Plastic objects Rail vehicles Road vehicles Shipwreck artifacts Silver objects South Asian household shrines Stained glass Taxidermy Textiles Tibetan thangkas Time-based media art Totem poles Vinyl discs Woodblock prints Wooden artifacts Wooden furniture
Intangible cultural heritage preservation	Ancient music Applied folklore Dance notation Early music Endangered language Ethnochoreology Ethnomusicology Ethnopoetics Family folklore Folklore Folk art Folk dance Folk etymology Folk instrument Folk medicine Folk music Folk process Folk play Foodways Folklore studies Heritage language Heritage language learning Indigenous intellectual property Indigenous culture Indigenous language Language death Language preservation Language revitalization Living history Oral history preservation Preservation of meaning Primitive music Tradition preservation Traditional knowledge
Notable projects	Conservation issues of Pompeii and Herculaneum Conservation-restoration of Ecce Homo by Elías García Martínez Conservation-restoration of The Gross Clinic by Thomas Eakins Conservation-restoration of Leonardo da Vinci's The Last Supper Pompeian frescoes Conservation-restoration of the Shroud of Turin Conservation-restoration of the Sistine Chapel frescoes Conservation-restoration of the Statue of Liberty Conservation-restoration of the H.L. Hunley Conservation response to flood of Arno, Florence Modern and Contemporary Art Research Initiative Preservation Metadata: Implementation Strategies World Heritage Site