PRESERVATION POLICIES
GLOSSARY
This glossary provides simple explanations of terms commonly used in library
preservation work. It is aimed at the non-conservator and is not exhaustive.
THE NATIONAL PRESERVATION OFFICE
This leaflet is sponsored by Riley Dunn & Wilson
ACID FREE PAPER Paper with a neutral or alkaline pH level (pH 7 or above) at time of
production. This may not be permanent.
ACID MIGRATION Movement of acid from one material to another.
ALUM Acidic compound used in the manufacture of paper to fix sizing agents onto cellulose
fibres.
ALUM ROSIN An acidic method of sizing used in the 18th century. Rosin, a size, is mixed
with alum to enable paper to be written on.
ALUM TAWED A process of treating prepared animal skins with alum salts. This leaves the
skins supple and creamy white in colour. The results are more permanent than tanning.
ARCHIVAL QUALITY PAPER/BOARD Material of a sufficient standard to be considered
suitable for long term use in the preservation of library or archive materials. Accepted opinion
is that it should be free from lignin and groundwood pulp, neutral sized with an alkaline
residual buffer of approximately 2.5%.
ART/COATED PAPER Paper with a smooth, glossy surface produced by coating with
china clay and casein glue. It is generally used for fine art books. All such papers are very
susceptible to water damage – the papers stick together and can become difficult or impossible
to part.
BANDS Ridges across the spine caused by the sewing support. Sometimes false bands are
used for decorative purposes.
BINDING Gathering of sections/leaves held in a structure, fastened together along one side
to form a spine, usually incorporated in a cover. Can range from paperbacks held together by
glue to quality sewn structures.
Among common binding structures are:
ADHESIVE/PERFECT Common modern binding style where single leaves are held
together with adhesive.
CASE Binding technique where the bookcover is not an integral part of the book structure
but is prepared separately from the textblock. It is glued to the textblock at the end of the
process.
CONTEMPORARY This means contemporary with the textblock, not ‘present day’.
FINE/DESIGN Hand binding using craft techniques and fine quality materials.
LEDGER/ACCOUNTS/STATIONERY Usually used to describe books with a spring
action in the binding. This throws up the spine so that the leaves lie flat when the book is
open.
LIBRARY Originally designed as a low cost durable binding. The boards and cover are
attached to the textblock in separate processes: the textblock is attached to the boards by cords
or tapes and the cover is then pulled around this structure. The corners and the spine are also
strengthened. It is far more durable than case binding.
Binding styles:
FLUSH Binding with the text leaves level with the boards. There are no ‘squares’ (see
below).
FULL Binding with the covering material in one piece.
LIMP A binding with flexible covers, without stiff boards. A term which can be used about
all covering materials.
HALF Binding with the spine and fore-edge corners in one material and the sides in a
different material.
HOLLOWBACK Binding with a paper tube between the spine and the covering material
which allows the covering material to move away from the spine on opening. The spine
cover thus retains its shape and the leaves can open more fully.
QUARTER Binding with the spine and some board area covered in a different material from
the rest of the sides.
SEMI-LIMP Thin flexible card or heavy paper is used for the boards. Often the board/card
is not stuck to the cover.
TIGHTBACK A binding construction where the covering material is adhered to the spine
BLEED Where the trimming of a book runs into the text or illustration, intentionally or
unintentionally.
BLIND TOOLING/STAMPING Blank impressions made by the binder’s finishing tools or
panel stamps on the covers of a book i.e. Not highlighted by ink or gilt.
BOARDS Hard covers on the front and back of a book.
BOLTS The folds at the heads and foredges of the leaves of a folded sheet, before they have
been trimmed. If the book is not being guillotined then the opening of these folds is done
with a knife and is known as ‘slipping the bolts’. The ‘spine bolt’ is sewn through.
BOOKCRADLE/REST Provides a support for holding a bound volume open without
strain, used most appropriately for exhibiting, mounting, study or microfilming.
BOOKWORMS Generic term used to describe a wide variety of insect pests harmful to
books, none of which are actually worms!
BOXING OR OTHER ENCLOSURES Popular preservation measure. A purpose built or
standardised box, which should be of archival standard materials, to protect a book or papers
from environmental, storage or human damage. Boxes can be covered in a variety of
materials.
Common types of box/enclosure are:
BOOK SHOE A sleeve made from thin card, cut and folded to fit unobtrusively round a
volume to protect and support the binding while it is on the shelf. The spine and head are
exposed to enable the book to be removed and inserted without damage. Must be made to
measure.
DROP SPINE BOX The spine of the box falls away on opening allowing the box to lie flat.
This gives access to the spine of the book allowing it to be removed easily without damage.
Must be made to measure.
DROP SIDE BOX The side(s) of the box fall(s) away on opening. This allows greater access
than a drop spine box and decreases the risk of abrasion to the book on removal.
PHASE BOX A relatively inexpensive, easily assembled structure of archival quality card, of a
suitable weight, cut and folded to fit snugly round the book. Essentially a temporary solution
(prior to conservation), but increasingly seen as a long term answer.
SLIP CASE A protective case which fits snugly round the volume leaving only the spine
visible. It is in fact potentially more hazardous than many other types of boxes because of the
risk of abrasive and other damage when inserting the book into the case.
SOLANDER BOX a) Box with a hinged lid to store documents, pamphlets etc. b) Box
with a removable top to store a book.
BRITTLE BOOK One with paper degraded to such an extent that it is fragile and could
break up on handling. It may or may not be discoloured.
BUCKRAM Common term for a heavy weave cotton or linen cloth used for binding and
box-making. It must be clearly qualified when making specifications.
BUFFER Substance used to control the acidity and alkalinity of a solution or material.
Conventionally used to describe an alkaline reserve.
COCKLING Uneven distortion of paper or parchment caused by unstable humidity levels.
CONSERVATION Denotes those specific treatments and techniques applied in protecting
library and archive materials from deterioration which involves intervention with the object
itself. Modern ethics demand respect for the historic integrity of the item.
CONSERVATION BINDING A much misused term. Should be used to denote the
stabilisation of an item to preserve the remaining parts of the structure and retain its integrity.
CONSERVATION BOARD An archival quality board containing no harmful properties
which could migrate to materials in contact with it.
CONSERVATION/PRESERVATION SURVEY A study to assess the physical state and
needs of a collection.
CROPPED Said of margins which have been so ruthlessly trimmed in binding that edges of
the text or illustrations have been sliced off. (See BLEED).
DEACIDIFICATION The process by which acid within paper is neutralised. (See
BUFFER).
DECKLE The edge of a sheet of handmade paper, which is always slightly uneven. In some
kinds of modern machine-made paper, rough edges are artificially produced in order to create
a handmade effect.
DISASTER An unexpected event which puts collections at risk. Most commonly a flood or
fire.
DOUBLURE A decorative panel lining the inner face of the boards. Usually made of leather
or fine textiles.
DRY CLEANING Surface cleaning using various mechanical methods e.g. eraser, brush, dry
cleaning powder.
ENCAPSULATION Process by which a single sheet is protected by placing it between 2
sheets of transparent polyester which is subsequently fused at the edges.
END/HEADBAND Hand-worked band of linen or silk sewn at the head and tail of the
spine. Sometimes machine-made bands are used and stuck on.
ENDPAPER Paper, often decorative, added at the beginning and end of a book, to aid the
attachment of the boards and counteract the pull of the cover on the boards. (See FLYLEAF
and PASTEDOWN).
FACSIMILE Exact copy of an original.
FASCICULE A sewn gathering of leaves which allows items to be inserted, with individual
support sheets, in the way each requires. Items can be simply tipped in to a support sheet or
attached to a guard. A very flexible system, designed as an improvement to guardbooks.
FINISHING Final treatments after text block has been put into covers (including
polishing/dressing of leather, tooling etc).
FLYLEAF Blank leaf/leaves adjacent to the first and last sections of textblock. (See
ENDPAPER).
FOLD TEST A technique to determine the number of double folds which paper can bear
before breaking.
FORE-EDGE Edge of the book opposite to the spine.
FORMATS (These terms are often used loosely to describe the size of books).
FOLIO a) A full sheet of paper folded once to form 2 leaves (4 pages). Individual folios can
be quired, i.e. placed inside each other, to give gatherings of 2, 4, 6, 8 leaves etc. Usually only
applied to printed books. b) Also used to describe a single manuscript leaf, either in a volume
or unbound collection of papers.
QUARTO A full sheet of paper folded twice to form 4 leaves (8 pages).
OCTAVO A full sheet is folded 3 times to form 8 leaves (16 pages).
DUODECIMO A full sheet is folded or cut 4 times to form 16 leaves (32 pages).
FOXING Red/brown spots on paper, attributed to the effects of micro-organisms on iron or
copper impurities in paper. Very difficult to remove safely.
FREEZE DRYING Process by which materials are dried in a vacuum held at temperatures
below freezing point. The ice changes into water vapour without passing through a liquid
stage.
FRENCH JOINT/GROOVE A groove formed at the outer joint between the boards and
the spine.
FUGITIVE Refers to non-permanent ink/colours which fade in light or are soluble.
FUMIGATION A gaseous process carried out under controlled conditions, to inhibit
microbiological growth and insect infestation.
GATHERING A sheet, or several sheets, of paper folded to form a single group of leaves in a
book. Sometimes referred to as a section, signature or quire.
GILDING Decorative and protective process involving the application of gold leaf to one or
more edges of the text-block.
GUARD a) An extension pasted onto a single sheet to allow it to be inserted undamaged
into a book. B) Meeting guard – a stub to which a section is sewn thus allowing books with
narrow margins to be read without forcing the binding. c) A folded strip of paper, which
operates as a hinge, attaching a single sheet item to a support.
GUARDBOOK A book of blank leaves, interleaved with short compensation stubs/guards,
for mounting single sheet, or very thin items.
GUTTER Blank space between the end of the text and the spine bolt.
HYGROGRAPH An instrument to measure relative humidity over a set period of time.
The results are presented in graph form.
HYGROMETER An instrument to measure relative humidity giving a digital/analogue on-
the-spot reading.
INTERLEAVED a) Binding where printed leaves alternate with blank ones. The blank
leaves are inserted for the owner to make notes on. b) Leaves inserted to protect the text-
block images.
JAPANESE PAPER/TISSUE A paper (traditionally handmade) produced in Japan from
mulberry, mitsumata or gampi fibres, used for conservation.
LAID PAPER Paper showing chain-lines and wire-lines produced by the wires of the mould
in which it was made.
LAMINATION The fusing or sticking of sheets of tissue, paper or film to one or both sides
of a sheet of paper.
LEAF CASTING Process by which missing areas in paper are in-filled using paper pulp.
LEATHER Skin of certain animals which has been preserved by tanning.
LEATHER DRESSING Compound which when applied sparingly will improve the
appearance and suppleness of dry leather.
LETTERING PIECE A label, usually of thin leather, which is lettered with the book details
and attached to the spine.
LIGNIN Non-carbohydrate substance which together with cellulose forms the woody cell
walls of plants, adding strength and bonding. Causes the acid that breaks down machine
produced paper.
LUX Unit of measurement of the intensity of light. It is technically defined as ‘a unit of
illumination produced by light from a source of one international candle falling normally on a
surface at a distance of one metre.’
MARBLING Decoration applied to the edge of the textblock or sheets or paper, by floating
pigments on a size and drawing into designs.
MATTING/MOUNTING Method of protecting prints, single sheets etc. Two pieces of
board are hinged together with the print in between. The base supports the print and a
window is cut into the top piece for viewing.
MICROFILM Most common form of substitution. Material is filmed in reduction on either
positive or negative film. Film is read through enlarging machines.
MISBOUND Used to describe a leaf or gathering wrongly folded or misplaced by the binder.
The term does not imply that anything is actually missing.
MOROCCO Originally used or high quality North African goat skin, but later used to refer
to any goat skin. Recognisable by its pronounced graining.
MOULD a) Law person’s term for micro-organisms that thrive in damp conditions e.g.
mildew, fungus. b) The sieve-like instrument on which the handmade sheet of paper is
formed.
MUSEUM BOARD The term suggests a high grade, archival quality, laminated paper board.
OPENING Two pages which face one another when the book is open.
PAPYRUS Writing material of the ancient Egyptians made from the papyrus plant. It is
made by placing one layer of flattened reeds at right angles to another.
PARCHMENT Originally the flesh side of a split sheep skin which was then treated in the
same way as VELLUM. Now used as a generic term to describe a split animal skin.
PASTEDOWN The endpaper which is pasted down onto the boards. (See ENDPAPER).
pH Chemical scale showing the negative logarithm of an effective hydrogen ion
concentration in a solution. Used to denote acidity or alkalinity on a scale of 1-14. Neutral =
pH7.
PRESERVATION A broader term than conservation. It includes all the managerial and
financial considerations including storage and accommodation provisions, staffing levels,
policies, techniques and methods involved in preserving library and archive materials and the
information contained in them.
PUBLISHER’S CLOTH The original cloth cover of an edition binding.
PULLING/DISBINDING Reducing a book to loose sections/leaves.
REBACKING Process in which missing or damaged spines and joints are repaired using new
materials. Original boards and spines are reused where possible.
RECTO a) Front of a leaf b) Right hand page of an open book.
REFURBISHING Basic cleaning, including the application of leather dressing, and minor
repairs to help slow down the rate of deterioration.
REJOINT Method of repairing a broken binding joint using a cloth or paper strip. (It is not
particularly strong).
RELATIVE HUMIDITY Refers to the amount of water vapour in air. It is calculated as a
percentage:
Amount of water in a given quantity of air
RH = Maximum amount of water which the air can hold at that temperature x 100
RESTORATION Denotes those techniques used in reconstructing damaged library and
archive materials to what is perceived to be their original form. It does not necessarily include
good conservation practices.
SIZE Glutinous substance used to decrease the absorbency of paper.
SQUARES Extension of the boards beyond the textblock.
STUB a) The narrow strip of inner margin which remains when a leaf has been cut out of a
volume. b) An additional leaf inserted with an extra width of margin to allow it to be sewn
in.
SUBSTITUTION The provision of a copy, often in microform, in order to protect the
original from use or overuse.
THERMOHYGROGRAPH An instrument which measures and records RH and
temperature over a set period of time. The results are recorded in graph form.
TIPPED IN Used to describe the process of inserting a single sheet into a book by pasting it
along one edge.
TOOLING The decoration or title on a book cover produced with hand-held tools.
UNBOUND Generally used to mean that a copy is not, and never has been, bound. Thus
distinct from ‘disbound’.
UV Ultra violet light – radiation beyond the visible spectrum at the violet end, which has
shorter wave length than those of visible light. UV light is particularly dangerous to library
and archive materials.
VACUUM DRYING Method of drying materials in a vacuum held at a temperature above
freezing point. The water evaporates to vapour.
VELLUM Animal skin, usually calf, which has been prepared by treating it with lime,
stretching and scraping rather than tanning.
VERSO a) Back of a leaf b) Left hand page of an open book.
WRAPPERS Paper covers which can be plain, printed or marbled. Commonly used as a
cheap temporary binding during the late 18 th and early 19th century.