The following definitions are used in the damage atlas:

Damage is a change of an object that has a negative effect on (1) the condition and value of the object either entirely or partly; (2) value of an object as a part of a collection; (3) the use of an object or a collection which it is part of.

The aim of this damage atlas is to describe only the physical damage to books, in other words, negative changes in the book materials and structure

As books are made up of distinct parts with characteristic types of damage, the atlas is also divided into three parts:
- textblock;
- leaf attachment;
- binding.

Textblock is formed by sheets that are attached on one side (sewn, wired, or glued). Covers are attached to the textblock.

The used evaluation method considers front sheets as belonging to the textblock; i.e. their condition is evaluated together with the textblock. The end leaf is the text that is glued or sewn to the first and the last sheet of the book (with single fold); the end leaves join the textblock and the covers. It is often decorated, marbled etc. Leaf attachment is attaching the sheets to form the textblock. The textblock of a printed work can either be glued, sewn, stapled, or combination of these can be used. Binding are formed by materials attached to the back and the sides of the textblock to protect it.

Physical damage that can occur in different book parts is divided into damage types. Damage types are distinct groups of damage that can easily be distinguished on the basis of features that are either morphological (shape, size, location, colour) or measurable by instruments (pH).

Most damage types can be detected visually. In order to facilitate this, descriptions of damage types have been presented with illustrative photos. Technical measuring instruments are only needed to determine the pH level (acidity) of the paper.

The extent of each specific type of damage can be different; this is described by damage category. Damage categories are presented in two manners. Some damages are described via four categories. This means that different degrees of damage severity are distinguished. With such damages, four categories are distinguished:
1 – not damaged;
2 – partly damaged;
3 – damaged;
4 – severely damaged.

With some types of damage, two categories are distinguished: not damaged / damaged.

Using the book condition calculator

The aim of describing the damage is to determine the book condition. The objectcondition describes the general physical state of an object. The general physical state of an object is related to materials, construction, structure, appearance, measurements and shape of the object. In determining the state, different types and categories of damage are summarized in order to reflect the summarized state indicators of the object.  The best way to find summarized state indicators is to use the book condition calculator.   

The book condition, similarly to damage categories, can be divided into four:
1 – not damaged;
2 – partly damaged;
3 – damaged;
4 – severely damaged.

It should be noted that condition assessments do not fall below four; i.e. all calculated results that are lower are rounded up to four.

Paper condition index are characterised by two integrated indicators:1) mechanical paper condition index and 2) chemical paper condition index. Mechanical paper condition index is found by taking the lowest category of the following damage types:
- sheets are torn;
- sheets have missing parts;
- sheet edges are worn;
- textblock is soiled.

Deformed textblock (positive answer to the damage type ‘textblock deformation’) lowers the mechanical paper condition index by one grade.

Chemical paper condition index is found by taking the lowest category of the damage type ‘Colour change of paper’ and lowered by one grade when the answer to the damage category ‘Foxing’ is positive.

When the book paper is brittle; i.e. breaks with three or less double folds, it receives the lowest assessment (four) of the paper condition index irrelevant to other indicators.

The paper condition index is found by taking the lowest assessment of the mechanical and chemical condition.

The leaf attachment condition index is characterised by the lowest category of the following damage types:
- loose sheets;
- binding.

With rusty staples (positive answer to the damage type ‘Corrosion of metal attachments’) the leaf attachment condition index  is lowered by two degrees.

The binding condition index is characterised by the lowest category of the following damage types:
- presence of covers and cover material;
- cover groove;
- cover corners and edges;
- back;
- surface material of covers;
- hinges.

The book condition index is an integrated indicator that characterizes the book as a whole, taking into consideration the condition of the paper, the leaf attachment and the binding, but also other examined features.

When determining the book condition index, the lowest assessments characterising the condition of the paper, the leaf attachment and the binding are taken into consideration. Positive answers to the following damage types decrease the general book condition by one degree:
- previous improper paper corrections;
- previous improper cover corrections;
- damage to headband;
- damage by insects.

Mold damage (positive answer to the damage type “Mold damage”) decreases the general book condition by two degrees.

As other integrated indicators, book condition cannot fall below four, meaning all larger values are rounded up to four.