Explanatory dictionary


Avers (Latin: avers)

The observe side of unbound parchment sheets; side with the text. The treated side of the parchment base skin. See: recto.

Base material

The base material is any material on which a text or image can be created. The concept of information carrier is also used as a synonym.


Book (Estonian: raamat)

Raamat, the word for book Estonian, is a loan from Old Russian, which, in turn, is based on the grámmata (plural), i.e. lettering. In the most general sense, a book is considered to be a volume intended for public use of a written or printed text of considerable length, made of materials that are light and strong enough to ensure the portability and handling of the texts. The primary function of a book is to present texts in order to convey information between people. A book is a means of human communication.


A rock-forming mineral consisting of calcium carbonate, CaCO3. Degradation of parchment and the formation of glass-like areas are often accompanied by the formation of a white precipitate of calcite or gypsum on the surface of the parchment.



Limestone, consisting primarily of calcite (CaCO3) and also containing various salts of magnesium (Mg) and calcium (Ca). Chalk is formed naturally, mainly from the chambers of microscopic marine animals.



Visually, it is possible to distinguish the characteristic features or peculiarities related to the original properties of parchment, which result from the properties of the skin, the manufacture and treatment of the parchment.



Parchment pages with handwritten text bound into a book, whereas both sides of the parchment sheets have been treated in the same way. The term ‘codex’ (Latin: cōdex, cōdic-, tree trunk; variant of caudex, trunk) dates back to the pre-parchment era, to so-called ‘bound’ books made of thin wooden strips coated with wax.



A protein, a high molecular weight compound that monomers of which are various amino acids joined together by peptide bonds. Collagen microfibrils are extremely long collagen molecules (about 300 nm) when compared to their cross-section (1.4 nm), and contain about 1,000 units in the molecular chain. The initial part of the fibrous structure is tropocollagen, which is organised into a right-handed α-helix by three polypeptide chains.



Visual assessment of changes in parchment properties. In order to assess the condition, it is necessary to identify the damage that has occurred. The visual assessment of the condition compares the initial condition with the condition of the object in the damaged condition. It is assumed that the object was originally physically intact and that the damage to the condition of the parchment has become visible visually during subsequent handling and storage. The concept of condition helps to define the physical integrity and preservation of parchment.


A change in the original properties of parchment that is visually visible, identifiable by a specific term, and that negatively affects the condition and values of the object, in whole or in part. Changes caused by the natural aging of the material are also considered to be damage.


Degradation or gelatinisation

Parchment degradation is caused by the breakdown of polypeptide chains of long (ca. 300 nm) collagen molecules, which were neatly twisted into a left-handed α-helix by hydrogen bonds, into shorter molecules as a result of oxidation and hydrolysis. The weakening or complete loss of the hydrogen bonds stabilising the molecules increases the degree of freedom of the molecules, resulting in the initially arranged α-helix-shaped collagen molecule acquiring the structure of a gelatin molecule with a partially or completely random orientation. This partial or total degradation process is called gelatinisation.



An essential structural part in the middle of the cross-section of untreated leather, consisting mainly of collagen fibres and bundles thereof that make the skin elastic after treatment. The dermis is the most collagen-rich area of the skin.


The outer layer of the skin, which consists mainly of protein keratin, which protects the lower layers of the skin from the external environment. Epidermis is the most keratin-rich area of the skin.

Forel (German: Futter)

This term was originally used for roughly treated sheep, pig and ox skin parchment that was used as a cover material for bound parchment sheets.

Goldbeater’s skin

When processing gold into thin gold leaves, a different type of 40- to 80-cm-long parchment made from the cecum of a calf was used as an aid. Short procedures with slaked lime were used for the processing. The cecum was elastic and very stretchable. The cecum yielded an ultra-thin, 0.05–0.01 mm thick elastic, but mechanically strong and long-lasting parchment.



Gypsum is a common an ordinary mineral, CaSO4·2H2O, and the most widely distributed of the sulphate minerals. The degradation of parchment and the formation of glass-like areas are often accompanied by the formation of a white precipitate of calcite or gypsum on the surface of the parchment.

Historical record (Estonian: ürik, German: Urkunde).

The Estonian word ürik is often used for all kinds of historical documents. It is useful to know that this term has a definite meaning. Historically, an ürik is a legally valid document with legal content. In a situation where there were few written records or none at all, such legally valid documents were the only ones that one could rely on to prove one’s rights.


Calcium hydroxide (Ca(OH)2). In the manufacture of parchment, the skin is soaked in a weak aqueous solution of slaked lime. This is a process that takes place in a strongly alkaline environment (acidity, pH = 10-12). When the parchment is dried after soaking, calcium carbonate (CaCO3) is formed in the parchment from lime and carbon dioxide in the air.



Non-collagenous components of the parchment. Lipids are non-polar biomolecules of the skin that contain esters and are insoluble in water. The higher the lipid content of historical parchments, the greater the risk of parchment degradation.


Common name for materials that can be applied to the substrate either manually or by other methods.

Palimpsest (scratched or scraped again)

Parchment page from which the text has been washed or scratched off, in order to be reused. This recycling method was already used for wax-coated clay slabs.



A processed material of animal origin. A strong, chemically resistant material made from the skins of mammals processed in a specific way and originally used for writing. Parchment was named after the city-state of Pergamon (now Bergama, Turkey), where the method for processing skins into writing material was invented. The origin of the word dates back Greek and Latin words meaning ‘writing material from Pergamum’. The original name of the treated skin in Latin was memranae, which was later replaced by the names repyapsivi, charta (thin leaf) or pergamena. This later evolved into Pergament in German, parchment in English, parchemin in French and pärgament in Estonian.


Parchment paper or pärgamiin

The name is used for a wide variety of products: plasticized cotton paper (paper vellum), heat-resistant paper, petroleum bitumen impregnated cardboard (parchment), semi-transparent or transparent paper of vegetable origin (parchment paper).



Porous rock of volcanic origin rich in sodium (Na) and silica (SiO2), which was used to finish the damp parchment and smooth the surface of the skin.

Recto (Latin: recto)

The treated side of the underside of the parchment skin, which was usually the front or face of the right-hand page of an open codex. As a rule, more velvety, softer than the coat side (verso). In parchment scrolls, this was the inner surface with the text. See avers.


Revers (Latin: revers)

The underside with the coat of an unbound sheet of parchment. See verso.

Section or folio

A component of the content block of the volume. For the production of historical parchment volumes, cut-to-size parchment sheets were folded in half into a sheet of two sheets, to form folios (also double leaf; Latin: bi-folio) comprised of four pages. The parchment sheets could be refolded into eight pages (Latin: quarto), and again into sixteen pages (Latin: octavo).



A skin thinning procedure whereby some of the layers of skin are separated by splitting the layers apart by physical force. Usually, the layers that are not strongly physically bonded together are separated over the entire surface of the skin. When mechanically splitting the skin, it is possible to either split off or remove the upper, epidermal layer of the skin surface. (i.e. hair-split parchment) or split off the subcutaneous layer (i.e. flesh-split parchment). To obtain an ultra-thin, uniformly thick vellum, bilateral splitting was also used. Sheepskin and goatskin that were pre-soaked could be split very easily. Several tools were used for splitting, which have now been replaced by machines.


Subcutaneous layer, flesh

The underlayer of the skin and the oiliest area. This layer is unevenly distributed throughout the skin and has a weak structural structure. When the skin is treated, this layer is mechanically removed either partially or completely.

Transparent parchment

Historically, in order to obtain transparent parchment, ultra-thin skin was treated with either linseed oil, an aqueous solution of fish glue or rotten egg whites. Transparent parchment was used for decorating and copying manuscripts, and making windows. In 1780, Edwards of Halifax patented the technology for producing transparent parchment. In order to achieve transparency, in addition to stretching and grinding, the underside was treated with potash, i.e. potassium carbonate (KCO3).

Vellum (Latin: vitulinum, French: velin)

Vellum was originally a high-quality parchment with certain properties, made of the skin of an unborn or newborn calf. Later, the scope of this name was expanded to include calfskin as a name for high-quality, double-sided parchment made of calfskin. As a rule, vellum was thinner than ordinary parchment. Vellum was the main material for the production of early (2nd– to 12th-century) manuscript volumes (codices). Today, the term vellum is often used as a synonym for parchment.


Verso (Latin: verso)

The coat side of the parchment sheet, which was usually the front or face of the left-hand page of an open codex. It was the outer surface of a parchment scroll. See revers.