The History and Technology of Parchment Making

Meliora di Curci

  1. Introduction

    There have been many different materials used as writing media throughout the history of human evolution. These have included stones, clay tablets, bricks, bark, wood, papyrus, linen, wax tablets, metal, ivory, bone, leather and paper (Reed, 1972, p. 1).

    In the recent times, the three main forms of writing media used above all else are papyrus, parchment and paper. This paper will concentrate mainly on parchment but will discuss the overlap of the other two forms where applicable.

    1. What is Parchment?

      Parchment is the processing of animal skins to produce a hard, durable, white material of even opacity and uniform thickness which will take pigments, inks and dyes in a suitable manner for writing (Kenyon, 1932, p. 87). Parchment is a specially prepared skin which is not tanned (Gansser, 1950, p. 2941).

      The animal skins are wet, covered in a lime solution, the hair removed, the skins placed back in the lime, the lime then washed off and the wet skin stretched and dried. While drying a number of different pre-treatments such as pumice and chalk were sometimes rubbed into the surface of the wet skin (Hunter, 1943, p. 14).

      Vellum versus Parchment
      There appears to be conflicting reports as to the definitions of these terms. Some authorities state that parchment made only from calfskin is known as vellum, while all other animals form parchment (Wheelock, 1928, p. 5). Other authorities state that vellum specifically refers to uterine parchment (Rudin, 1990, p. 10). Other authorities state that vellum refers to high quality parchment only. Reed (1975, p. 79) sums up this dilemma best when he states both terms seem equally valid. To avoid confusion, this paper only uses the term parchment, except when directly quoting another source.

  2. History
    1. Leather and Skin

      As early as the late Assyrian period (8th Century BC) the inhabitants of Mesopotamia preferred animal hides to clay tablets for writing, and according to Herodotus, wrote on unhaired sheep and goat skins (Gansser, 1950, p. 2941). Inscriptions from Denderah state: after the finding of decayed leather rolls from the days of King Kheops (c. 2575 BC) (Reed, 1972, p. 4).

      The simplified tanning process used to make leather (see section 3.1) created difficulties in drying the wet leather to a smooth, flat sheet free of wrinkles and undulations (Reed, 1975, p. 40) which detracted from their widespread use, leaving papyrus the dominant writing media (Reed, 1975, p. 37).

      Wheelock (1928, p. 4) refers to a manuscript on the Sorbonne of Paris that was apparently written on tanned human skin. This item has not been corroborated by any other readings for this paper.

    2. Parchment

      In the second century BC a library was set up at Pergamum in Asia Minor by King Eumenes II. Pliny wrote in his Natural History, Book XIII, passage XXI:

      Subsequently, also according to Varro, when owing to the rivalry between King Ptolemy and King Eumenes about their libraries, Ptolemy suppressed the export of Papyrus, parchment was invented at Pergamum and afterwards the employment of the material on which the immortality of human beings depends, spread indiscriminately." (Reed, 1975, p7)

      The significant innovation at Pergamum was that by simplifying the liquor bath and drying the pelt in a stretched state, it led to the creation of extremely durable, smooth taut sheets of uniform opacity of a pale colour known as parchment (Reed, 1975, p. 43).

      In 1909 two parchment documents were discovered at Avroman in Kurdistan, which bear dates equivalent to 88 BC and 22BC. Also in 1923 excavations at the site of the Roman fortress of Dura discovered more parchment documents which correspond to the dates of 189-196 BC. This leads some authorities to believe that parchment was in use before the time of the Pergamum library, and the Pergamum simply refined the process (Kenyon, 1932, p. 89).

      Towards the end of the first century BC, parchment began to increase in popularity due to the availability of off cuts to be used for ephemera such as tags and labels (Reed, 1975, p. 47). Other advantages of parchment over papyrus was its flexibility and the fact that both sides of the parchment could be written on. Also the writing was easier to read and corrections easier to make (Reed, 1972, p. 5). By the third century AD, parchment was the preferred writing medium for all purposes (Reed, 1975, p. 53).

    3. Scroll versus Codex

      In the early Roman period single sheets were generally used for ephemera such as speech drafts or memoranda, but until 200 AD texts of any appreciable length were on scrolls (Reed, 1975, p. 58). Papyrus and parchment scrolls were constructed in similar manners but whereas papyrus was merely glued together, the parchment sheets were stitched. The parchment scrolls therefore had a stronger join and were more durable (Reed, 1975, p. 58).

      During the first two centuries AD the scroll gradually disappeared in favour of the codex. Kenyon (1932, p. 119) believes that scrolls were used by pagan religions and the codex was brought to prominence by the early Christian religions. Reed (1972, p. 5) believed that the ease in which parchment can be made into a codex (while papyrus was not structural suitable) could be the main reason, but then in 1975 (p. 58) Reed believed the reasons for this are more obscure; either way they are certainly outside the realm of this paper.

    4. Specialised Parchment Types

      Due to the range of tasks that parchment was required for, a number of specialised parchment types came into being.

      1. Uterine Parchment

        During the middle ages, some parchment was made from the skins of unborn animals. In the animal foetus, the skin develops early so that at a tender age it has a well-formed dermal network which is both thin and strong. It also has minimal if any hair to be removed. Due to these properties, uterine parchments were highly regarded as quality materials (Reed, 1975, p. 76). Uterine parchments could have easily been made from sheep, goats and calves, but due to the small sizes of these skins, calves were the main material used, as they retained the largest cutting area (Reed, 1975, p. 77).

      2. Goldbeater's Parchment

        Goldbeater's parchment was made from the caecum of cattle intestine. This form of parchment was processed and formed the same as ordinary parchment, It is however thin, tough, resilient and can stretch without breaking. Goldbeaters use it to separate sheets of gold when building a block which can then be hammered into finer leaves of gold (Reed, 1975, p. 77).

      3. Transparent Parchment

        There was a requirement for transparent forms of parchment in the scriptoria for scribes to use as "tracing paper" for tracing decorative elements when illuminating manuscripts. Transparent parchment has also been used in spectacles, magnifying glasses and as a window material when glass was not available (Reed, 1975, p. 85).

    5. Introduction of Paper

      Up to about 1520 AD parchment remained popular and the trade guilds supplied sufficient quantities for book producers, but at this time, paper and printing from movable type had become firmly established (Reed, 1975, p. 95). Even after the advent of wood-block printing and moveable metal type, parchment did continue to be used (Hunter, 1943, p. 16) but mainly as a binding material to cover paper books. Even this trade died out in the 17th Century as these bindings were considered to be too plain. Reed (1975, p. 95) sums up the current usage of parchment as follows:

      Parchment continues to be made, being used for legal documents, archival records, warrants and certificates, but its total production is now very slight and, apart from copies of historically important texts, literary works are rarely committed to its surface.

  3. Technology
    1. Early Tanning Process

      An 800 BC Sumerian account gave the following for dressing a fresh ox-hide:

      This skin, you will take it, Then you will drench it in pure pulverised Nisaba flour, in water, beer and first quality wine, With the best fat of pure ox, the alum of the land of the Hittites, and oak galls, you will press it and you will cover the bronze kettle-drum with it(Reed, 1976, p. 25).

      And a Carchemish text of about 600 BC reads:

      You will steep the skin of a young goat with the milk of a yellow goat and with flour, you will anoint it with pure oil, ordinary oil and fat of a pure cow, You will soak the alum in grape juice and then cover the skin with gall nuts (Reed, 1975, p. 25).

      Early tanners appear to use a very simple done liquor baths approach to tanning skins. The bath generally contained warm aqueous solutions of vegetable matter consisting of twigs, stalks, leaves, nuts and fruit of soft green plants and/or wood, bark and galls of shrubs and trees (Reed, 1975, p. 26). The plant matter would ferment naturally and the enzymes produced would break down the plant carbohydrates to smaller organic substances such as lactic or acetic acids (Reed, 1975, p. 26). The bath served three processes:

      1. Dehairing: The enzymes in the liquor bath loosened the base of the hair follicles, allowing the hair to be easily and mechanically removed (Reed, 1975, p. 28).
      2. Loosening: The enzymes also loosened and digested some of the other substances in the dermal network which effectively cleaned the pelt and allowed individual fibres to expand by absorbing the organic acids from the bath (Reed, 1975, p. 28).
      3. Cleaning: The fermentation of the vegetable matter produces carbon dioxide gas within the fibre network of the pelt which, when rising to the surface of the bath, further help to clean the pelt (Reed, 1975, p. 28).

        When the pelts were removed from the liquor bath, the hair was scraped off with a knife. Similarly the flesh side was scraped clean and smooth (Reed, 1975, p. 28). The vegetable tannins produced by the liquor bath introduced chemical links between the larger fibres of collagen in the dermal network which turned the skins into tanned leather (Reed, 1975, p. 29).

    2. Tanned Parchment

      The majority of parchments up to 200BC appear to have been formed in the same manner as the tanned leather above, with the addition of the fact that the wet pelt was stretched for drying. Whenever liquor baths of fermenting vegetable matter were used, there was some chance that the resulting parchment would be vegetable-tanned (Reed, 1975, p. 43).

      It was only when the pelt preparation baths were simplified by excluding materials rich in vegetable tannin, that the parchments manifested properties different to leather (Reed, 1975, p. 43).

    3. Parchment Making Process

      According to Reed (1975, p. 72) the first known text on parchment making is the Lucca Manuscript written in a Northern Italian monastery in the 8th Century AD:

      How parchment is to be prepared: place [the skin] in lime water and leave it there for a few days. Then extend it on a frame and scrape it on both sides with a sharp knife and leave it to dry (Codex 490).

      Theophilus, a 12th Century scholar has a more detailed set of instructions:

      Take goat skins and stand them in water for a day and a night. Take them and wash them until the water runs clear. Take an entirely new bath and place therein old lime and water mixing well to form a thick cloudy liquor. Place the skins in this, folding them on the flesh side. Move them with a pole two or three times each day, leaving them for eight days (and twice as long in winter). Next you must withdraw the skins and unhair them. Pour off the contents of the bath and repeat the process using the same quantities, placing the skins in the lime liquor and moving them once each day over eight days as before. Ten take them out and wash well until the water runs quite clean. Place them in another bath with clean water and leave them there for two days. Then take them out, attach cords and tie them to the circular frame. Dry, then shave them with a sharp knife after which leave them for two days out of the sun. Moisten with water and rub the flesh side with powdered pumice. After two days wet it again by sprinkling with a little water and fully clean the flesh side with pumice so as to make it quite wet again. Then tighten up the cords, equalise the tension so that the sheet will become permanent. Once the sheets are dry, nothing further remains to be done. (Reed, 1975, p. 74).

      1. Choice of skin

        A wide variety of skins seemed to have been used to make parchment, predominantly calf, sheep and goat. Reed (1975, p. 19) states that and goat skins were preferred to be used as actual manuscript leaves while pigs or hog skin was used for bindings. However, Szczepanowska (1999, p. 38) carried out an analysis of a sample of 14th Century books of edicts from the Order of St John; all parchments examined were determined to have been made from goat skins only.

        Reed (1975, p. 76) quotes a dialogue between two 15th Century French Monks:

        In my skin are the prayers and all the blessings made to Holy Church

        And have not calves, goats, kids, Coneys, hares and cats skin? As vellum they may be well written upon? To be sure their parchment is worth more than your skin which serves you less.

        Reed (1975, p. 76) quotes a 10th Century text from Cordova, Spain:

        parchment from the inner layers of deer and gazelle skinsKenyon (1932, p. 86) also refers to a practice of using antelope skin.

      2. Soaking the Skin

        The first step in creating parchment, is to wet or soak the recently flayed skin in water. This process removes blood, dung and other organic matter, but it also wets all parts of the skin to allow easier penetration of the dehairing liquor (Reed, 1975, p. 80). In modern practice this soaking is carried out as rapidly as possible, finishing off with running water to minimise the loss of skin fibres by any bacterial action which might result from the use of static baths (Reed, 1975, p. 80).

      3. The Liquor Bath

        It is not known when lime was first used in the preparation of skins, (Gansser, 1950, p. 2944) but it is apparent from the Lucca manuscript that they were used by the 8th Century AD. However, there appears to be no evidence that these lime baths had replaced the earlier method of using baths of fermenting vegetable matter (Reed, 1975, p. 80). Indeed, the Book of Kells an 8th Century calfskin parchment shows no evidence of being placed in a lime bath, or even that any form of acid or alkali was used in its preparation (Cains, 1992, p. 54).

        The purpose of the lime bath is to soften and dissolve the epidermal layer that lines the hair follicles thus making the hair easier to remove (Cains, 1992, p. 50). There also appears to be some evidence that urine was used as an alternative to lime to complete this task (Gansser, 1950, p. 2941).

        According to Reed (1975, p. 81) the dehairing liquors would have been contained in wooden or hollowed out stone vats of approximately 2 metres long, 1 metre wide and 1 metre deep. Reed also states that these vats would have contained one or two dozen skins at a time. Metal vats would not have been used due to the potential of metal-staining the skins.

        As lime is only slightly soluble in water, the lime baths are relatively weak. However, they are still very efficient and dangerous to human skin; hence Theophilus' instruction to use wooden poles to move the skins around to ensure a uniform reaction within the lime bath (Reed, 1975, p. 81).

      4. Removing the Hair

        The skins were removed from the bath and, while still wet, were draped over a wooden or stone beam. The loosened hair could be removed using a metal or stone knife. Reed (1975, p. 81) believes that the hair was so loose that it could be pushed off with the hands, provided they were protected by stout gloves.

      5. Resoaking and rewashing

        Reed (1972, p. 81) considers the second lime bath suggested by Theophilus to be a sound practice as the action of lime on the dermal fibre network layer is slow. He believes that if the time devoted to liming is curtailed, then the skin may be uneven in character, thus difficult to stretch evenly which leads to parchment of variable colour and opacity.

        However, if the skin is left in the lime baths too long, then the fibre network may become too weak, developing holes in the dermal layer and the skin may not be able to withstand the stretching required for parchment (Reed, 1972, p. 81).

        Reed (1972, p. 82) also states that plain lime baths are too slow for commercial modern production of parchment and leather and the lime is now augmented by the addition of sodium sulphide into the bath.

        After the second lime bath, the skin is well washed in running water to remove any traces of lime left adhering to the skin. Any residual lime can cause the same problems as if the skin was left lying in the lime solution (Reed, 1972, p. 82).

      6. Stretching

        When the skin is removed from the liquor bath, the fibre network is runs in all directions and is very meshed. If the fibres have not been excessively tanned, the fibre network may be stretched when drying. This leads to a number of the fibres being broken under tension when drying and this allows the remaining fibres to become aligned into layers parallel to the grain (Reed, 1975, p. 44).

        The stretching is accomplished with the aid of smooth pebbles of stone which were pressed around the edge of the wet skin. One end of stout cords were tied around the pebbles and the other end attached to a drying frame, thus the skin could be dried under tension (Reed, 1975, p. 82).

        The frame was usually an open form which allowed both surfaces to be worked on at the same time. Both sides of the skin were scraped with a sharp knife to smooth the surface and produce a sheet of uniform thickness. Mostly the work was carried out on the flesh side, as the grain side merely needed any remaining fine hairs to be removed (Reed, 1975, p. 82). The knife does not cut through the skin, but rather pushes and separates the softened fat, flesh and gland tissue from the tougher collagen fibre (Cains, 1992, p. 50).

        If the skin is not placed under sufficient tension, rougher grains and transparent regions may develop in the dried parchment (Reed, 1975, p. 84).

      7. Drying

        During the drying process, the decomposed collagen glue also dries to a firm consistency and sets the layers of fibres into the stretched condition; the fibres cannot revert to their former relaxed state. Reed (1975, p. 44) sums up the process thusly:

        This results in a highly stressed sheet which is smooth, strong, relatively inelastic, light in colour, yet opaque: a material which may properly be called parchment.

    4. Pre-use treatments

      Before the parchment was used by the scribes, it usually underwent a number of pre-treatments to improve smoothness and ability to absorb the correct amount of inks and colours (Reed, 1975, p. 87). Other desirable attributes were to increase whiteness of the surface, remove stains and drops of fluid and to enhance grain patterns if required (Reed, 1972, p. 147).

      1. Pouncing

        Pouncing is the rubbing of pumice powder into the flesh side of the parchment in order to produce a smooth, silky nap to which the inks will adhere. It also allows the inks to penetrate deep into the fibres which adds to the permanence of the writing. As this treatment requires the parchment to be damp while the pumice is applied, it needs to be conducted while the parchment is still on the drying frame (Reed, 1975, p. 88).

      2. Stanchgrain

        Stanchgrain is the common name given to a variety of thin pastes comprised of varying quantities of lime, quicklime, flour, egg white and milk. When these pastes are rubbed into the parchment surface with a damp cloth, they produced an extremely smooth, hard, even, white appearance. The varieties of as stanchgrain were believed to create parchments of outstanding quality (Reed, 1975, p. 91).

      3. Other treatments

        The variety of treatments for parchment can be simple or complex and are designed for a number of different reasons; to prevent ink from running, to even out the surface or to whiten the appearance (Reed, 1975, p. 90).

        The running of ink and poor adhesion of ink were thought to be due to an excess of grease left in the parchment after the lime bath, hence a number of different solutions were devised to remove the grease at this stage of the process. These treatments were mainly composed of calcium compounds such as lime, chalk or woodash and were applied as either dry powders or wet pastes (Reed, 1975, p. 90).

        Szczepanowska (1999, p. 39) analysed a sample of 14th Century books from the Order of St John; the calcium carbonate in the samples of ground were identified as a mixture of calcite (CaCO3) and vaterite; a form of CaCO3 that rarely occurs in nature. Szczepanowska believes the presence of vaterite may indicate that the calcite used for the pre-treatments was of artificial origin.

      4. Colouring Parchment

        Clark (1979, p. 620) quotes a 5th Century vulgate Bible currently housed in the Capitular Library of Verona which was written on crimson vellum, which has since aged to purple; thus it is not safe to assume all parchments were white.

        Cennini, a 15th Century craftsman provides recipes to tint parchment a variety of colours including purple, indigo, green red and peach. He was also aware of the changes this would wrought in the parchment, and so offers the following advice:

        When you want to tint kid parchment, you should first soak it in spring or well water until it gets all wet and soft. Then, stretching it over a board, like a drum skin, fasten it down with big-headed nails, and apply the tints to it in due course, as described above.(Thompson, 1960. p. 10)

      5. 3.4.5 Byzantine Pre-treatments

        Byzantine parchment is characterised by a glossy smooth surface. It is believed that Greek parchment-makers polished it thoroughly and used egg-white and flax-seed and to obtain such an effect (Bykova, 1993, p. 188).

        Unfortunately, there are no historical documents on the methods to manufacture parchment in medieval Greece are known. Kireyeva (1999, p. 40) confirmed with thin-layer chromatography that egg-white and linseed extract were used to coat the parchment on a sample amount of Byzantine manuscripts dating from 11th to 14th centuries AD. Dried albumen is very fragile and required the linseed extract to give the treatment the elasticity and strength necessary for a surface coating. As it is obvious that the treatment was applied more thickly on the flesh side of the parchment, it is assumed this was to make the two sides indistinguishable for use (Kireyeva, 1999, p. 41).

        Only one other surface treatment was found by Kireyeva (1999, p. 42) consisted of a coating of collagen glue, casein and lead white. It has been assumed that this was applied by 14th Century Byzantine Parchment-makers in Constantinople.

    5. Transparent Parchment Process

      Mostly transparent parchment seemed to be used in the scriptorium based on the number of recipes provided by the monasteries. One such 15th Century recipe is:

      To make parchment as though it were glass take a thin parchment preferably from a kid slain which is already reasonably transparent. If you can find such a parchment scrape it with a knife as thinly as possible. Then soak the scraped parchment in the whites of eggs which have been allowed to go rotten, or in a watery solution of gum Arabic in a fish glue which has been diluted with water or in a glue made by filtering through a cloth or a glue made from the shavings of this or any other parchment.

      Then, when the parchment has been softened in one of the above ways, stretch it on a frame as you stretch parchments normally after taking the pelt from the lime bath. When the parchment is dry it is ready. But when it seems after drying that it had insufficient of the liquor, take a sponge moistened with the latter and smear the parchment on both sides until you think it is all right. And then if you place the parchment over any picture the latter is clearly visible through it and you can draw upon the parchment a true likeness of the picture you wish to copy (Reed, 1975, p. 85).

      This particular recipe recommends that to make the parchment transparent it should be rubbed with highly hydroscopic substances, but Reed (1975, p. 85) believed that the transparency may have been more influenced by the lack of tension under drying such as discussed in Section 3.3.5 of this paper. This is evidenced by the following recipe from Cennini (a 15th Century craftsman) which uses an oil which is not highly hydroscopic:

      If you want it more transparent, take some clear and fine linseed oil; and smear it with some of this oil on a piece of cotton. Let it dry thoroughly, for the space of several days (Thompson, 1960, p. 12).

      In 18th Century England, Edwards a famous bookbinder, in 1785 devised a new process of producing transparent parchment by steeping ordinary parchment in a solution of potassium carbonate and drying it by pressing it between two wooden boards without any form of stretching (Reed, 1975, p. 87).

  4. Chemical Properties

    The lime bath and mechanical dehairing in the preparation of parchment leaves the animal skins consisting almost entirely of collagen fibres. These fibres are composed of long chains of amino acids; mainly glycine, proline, hydroxyproline. Chemical bonds between these chains maintain the fibre structure and render it insoluble in cold water (Woods, 1995, p. 222).

    Collagen will dissolve in water on heating if it has been exposed to prolonged treatment with acid or alkali (such as the liming process) which causes breaks in the intermolecular bonds (Woods, 1995, p. 222).

    When heated to 65oC for unprocessed skins or 55-60oC for limed skins, the intermolecular amino acid chains shrink to about one-third of their original length, causing the collagen to become rubbery in texture. On boiling in water, the amino acids chains separate and go into solution forming gelatin (Woods, 1995, p. 222).

    Parchment requires the natural fibre weave of the skin to be changed to a horizontally layered structure by applying tension to the skin. (Woods, 1995, p222) When the wet skin is mechanically stretched, it rearranges the fibres into the layered structure and the drying of the gelatin keeps the fibres there. As wet skin dries in the air, water is lost from between the fibres within the skin and the high surface tension draws the fibres together. Adjacent fibre surfaces firmly stick to each other, causing a translucent and rigid sheet. During parchment production, tension is applied to the wet skin, causing the water to be forced out from between the fibres. Spaces between fibres remain and the dry skin is flexible and opaque (Woods, 1995, p. 222).

    1. Durability

      The main reason for the permanence of parchment is its ability to absorb or release water vapour to the atmosphere. A sheet of ordinary parchment (not having any surface treatments referred to in Section 3.4) contains about 10% of its weight as water at a relative humidity of 50%. (Reed, 1975, p. 92).

      1. High Relative Humidity

        If the atmosphere becomes damp at around 70% Ð 80% relative humidity the water content in the parchment will increase to about 25%. However this is a slow process since two to five days in required for this to occur. If this happens, the parchment sheets will cockle and then become soft and limp reverting to the wet pelt state with the loss of the characteristic layered arrangement of the fibres. Similar results would occur if the parchment comes into prolonged contact with liquid water (Reed, 1975, p. 93).

        Some of the treatments used on the manuscripts were designed to minimise this form of damage by sealing the pores of the parchment and incorporating traces of alum, fats or vegetable tannins into the fibre network (Reed, 1975, p. 93).

      2. Low Relative Humidity

        Prolonged exposure to an environment under 40% relative humidity will dry out parchment and bring its water content to below 10%. Once again this is a slow process which may take several months or years. Prolonged exposure to this environment will turn the parchment harder and harsher, eventually cracks would appear in the surface and the inks and paints will detach (Reed, 1975, p. 94).

        Once again some of the medieval pre-treatments minimised the rate of water absorption or loss. To counter the effects of alum, fatty substances and vegetable tannins (described in section 4.1.1), some hydroscopic substances were introduced included gum arabic, honey, parchment glue and egg white (Reed, 1975, p. 94).

  5. Summary

    Parchment plays an important process in the history of writing and recording human evolution. The processes by which parchment is made and used are extremely complex but also extremely effective as evidenced by the different number of functions it was used for and the quantity of manuscripts that are still in existence today.

  6. Bibliography

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    Cennini, Cennino d'Andrea. (1933). Craftsman's Handbook "Il Libro dell'Atre". Thompson, D. V. (Trans.) New York: Dover. (Original work published 1437)

    Clark, Harry. (1979). Special Report: the restoration of manuscripts at EuropeÕs oldest library. Wilson Library Bulletin, 53(9), 620-621.

    Gansser, A. (1950). Early History of Tanning. Ciba Review, 81, 2938-2962.

    Hunter, Dard. (1943). Papermaking: the history and technique of an ancient craft. New York: Dover Publications.

    Kenyon, Frederic G. (1932). Books and Readers in Ancient Greece and Rome. London: Oxford Clarendon Press.

    Kireyeva, Vilena. (1999). Examination of Parchment in Byzantine Manuscripts. Restaurator, 20, 39-47.

    Reed, Ronald. (1972). Ancient Skins Parchments & Leathers. Leeds: Seminar Press.

    Reed, Ronald. (1975). The Nature and Making of Parchment. Leeds: Elmete Press.

    Rudin, Bo. (1990). Paper or not? Papyrus, tapa, amate, rice paper and parchment. Making Paper, a look into the history of an ancient craft. Tanner, Roger G. (trans.) Vallingby, Sweden: Rudins, 1-10.

    Szczepanowska, Hanna & West Fitzhugh, Elisabeth. (1999). Fourteenth-century documents of the Knights o f St. John of Jerusalem: analysis of inks parchment and seals. Paper Conservator, 23, 36-45.

    Wheelock, Mary E. (1928). Paper: its history and development, Chicago: American Library Association.

    Woods, Chris.(1995). Conservation Treatments for Parchment Documents. Journal of the Society of Archivists, 16(2), 221-238.



