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Acid-Free
refers to paper-based materials that do not contain free acid and have a
pH value of 7.0 or higher at the point of manufacture. These materials may, however,
become acidic over time due to a lack of buffering agents (Alkaline Reserve) and the presence
of Lignin (a component of low-quality paper) or certain additives.
Acid Migration
is a process that occurs when acid transfers from a material containing higher acidity levels
to one containing less or no acidity. This may occur through off-gassing (gaseous transfer)
or physical contact.
Adhesive Binding
is type of binding in which single leaves are secured together solely with an adhesive applied
to the textblock's spine edge. Animal glues, polyvinyl acetate
(PVA) glues, and hot melt adhesives have all been used in the past for this type of
binding, sometimes refered to as "perfect binding". Sections with
perforations along the folds (or adhesive penetration into the folds to hold
each section together) is also a type of adhesive binding, commercially known as
perfo-, burst, mecha-notch, or perfopunch binding. See also
Double Fan Adhesive Binding.
An Alkaline Reserve
is a substance (commonly a calcium or magnesium salt) that has been added to
the paper matrix either during manufacture or after, which neutralizes active
acids and reduces the potential for the embittlement of paper. Papers that
have an alkaline reserve are referred to as Alkaline Buffered.
Archival and Archivally Sound are terms that
imply that a material or product is permanent, chemically stable, and durable.
However, there is no standard by which a material can be referred to as
"archival". Therefore, terms such as
acid free,
pH neutral,
alkaline buffered, or
lignin free may be better guides for the permanence of a material.
Archival Papers
(such as Permalife, Perma/Dur, or archival tissues) are made of high quality
paper fibers and frequently have an alkaline reserve
(pH 8.5). They are used for interleaving
sheets between acidic documents, for tabs for forms placed in contact with
archival materials, and to make simple wrappers when more protection is desired
than interleaving. It is important to use archival paper for preservation
photocopying or for the printing of new publications.
A text that has Artifactual Value is important as a physical object,
in addition to (or rather than) being important for the information it contains.
Examples of this include copies of books signed by the author, original
photographs, marginalia by famous owners/researchers, and highly decorative
bindings.
Barrier Sheets are pieces of archival paper inserted in a book or
placed between documents to prevent the transfer of media, acids, or damaging
gases from one material to another. See also
Interleaving.
Backing is the process of shaping a ridge or shoulder
on each side of the spine of a text block after rounding it,
and prior to lining it. Backing accommodates the thickness of the boards, and provides
a hinge along which they swing. Backing also helps to prevent the spine
of the text block from collapsing into a concave shape over time. See also
Rounding.
Board is a general term used for any stiff material used to form the foundation
for a book's case. They are made of various pulped or laminated fibrous materials
pressed into large, flat
sheets, which are then cut to size and covered with book cloth, buckram,
leather, paper, or other materials, to form the case. The boards are
referred to separately as the front and back boards.
Book Cloth is specially prepared cloth material used as a covering
material for the case. It is a thin, woven cloth that has
been dyed, filled, impregnated or coated with some compound, and subjected to
heat and pressure. Book cloth falls into three main categories: starch-filled,
acrylic-, pyroxylin-, or vinyl-impregnated, and plastic coated. Book cloth is
lighter weight than buckram and is available in a range of grades and
colors.
Boxes are containers used to hold loose sheets, documents, maps, or
fragile books. Commercially available and hand-made boxes are constructed of
many different materials and in many styles, including light-weight 4-flap
boxes, heavier phase boxes, and sturdy clam-shell/drop spine boxes.
Bristol Board is a high quality heavy weight paper, sometimes made
with cotton fiber prepared or glued together, usually with a caliper thickness
of
0.006" and up.
Brittle Paper occurs when acidity increases causing the molecular
structure of the cellulose fibers to weaken. This results in paper with reduced
fold-endurance which breaks easily when it is bent or folded.
Buckram is a heavy-weave cotton cloth filled, impregnated, or coated with
different compounds (mainly, starch and pyroxylin but also other materials) to
enhance body, finish, and durability. Most bindings from library commercial
binders have buckram cloth. C-Grade buckram is a thinner, smoother cloth than
F-Grade buckram, which is heavier and the most durable.
The Case of a book consists of two boards, a spine
inlay, and covering material (usually book cloth, buckram, paper,
or leather). The case is made separately from the text block and
is later attached to it in a step called Casing-In. See also Cover.
Case binding is a method of binding in which the case is made separately
from the textblock and later attached to it. (As distinguished from
leather bindings where the cover is assembled on the book.) The textblock is
attached to its case by means of its endsheets and an adhesive. This
method is used for most in-house book repairs and commercial bindings
Case Repair: A repair performed in-house to restore an original
hard-bound cover when the only damage it has sustained is a torn or damaged
spine.
Casing-In is the action of applying adhesive to the outermost endpapers
of a text block and fitting the text block into its case.
Coated paper is a type of paper coated with white clay or a similar,
synthetic substance to provide a smooth surface for printing detailed
illustrations. The finish is often glossy but can be dull. Most popular
magazines are printed on coated paper.
To Consolidate a spine is to attach the loose gatherings on spine edge
of the text block to each other and to a cloth support using an adhesive.
The Cover of a book is a more generic term than case, used to
imply any protective covering used on the outside of a book. Covers may be built
onto the book (including laced-on boards and tight-back leather bindings), can
be built separately from the textblock (including most modern cases),
or be of simple, paperback construction.
Deacidification is a process that impregnates paper with an alkaline
reserve to neutralize the active acid in the
paper substrate and act as a buffer to neutralize acids produced in the future.
Deacidification lengthens the life expectance of paper several times its
ordinary life.
Disbinding is the action of removing the textblock from its cover
or binder by easing the endsheets away from the textblock and by slitting
the super (if present) with a scalpel.
Double Fan Adhesive Binding is a type of adhesive binding where the spine
margin of each leaf in an unglued textblock is exposed 1/16"
or less for an application of adhesive. The margin is exposed on both sides of
each leaf by clamping the textblock on a vise-like press and then pushing
against the textblock, first in one direction, then the other, thereby fanning
or separating the edges of the leaves.
Encapsulation is process of creating a protective enclosure for flat
materials by placing the object between two sheets of polyester film and then
sealing it on at least one, but often all four edges using double sided tape,
heat, or ultrasonic
energy.
End Papers are the pages at the beginning and end of a volume added to
both protect the textblock and to secure it into the cover. End
papers include both paste-downs and flyleaves.
Flat back (sometimes referred to as square back) is a textblock
that has not been rounded or backed.
Flyleaf is the leaf (or leaves) forming that part of the folded endsheet
not pasted down to the inside of the cover boards. Its function is to protect
the first or last leaves of the textblock. See also End Papers and
Paste-down.
The Fore Edge is the edge of a leaf, textblock, or a board
opposite from, and parallel to, its spine edge. Fore edge is also used in
a more general way to refer to any part of a volume opposite from and parallel
to its spine.
Foxing are spots or irregularly shaped stains that occur on paper. Foxing
is caused either by fungi or iron impurities in paper, thought to be introduced
during the paper's manufacture. Foxing may be controlled by maintaining
relative humidity levels below 50%.
Gathering: see Signature
Grain Direction refers to the direction in which the majority of the
fibers in a piece of paper or board are aligned and to the direction in which
the warp threads run in cloth. Grain direction in all materials used in
bookbinding should run parallel to the spine of a volume.
The Gutter of a volume is the groove and combined margin-space
formed by the two inner or back margins of facing pages of a volume; closet to
the spine.
The Head is the top edge of a leaf, board, or bound
volume, opposite from the surface on which the volume rests when it is shelved
upright. See also tail.
A Headband is a small ornamental band, generally of cotton or silk,
which, in most modern publisher's trade bindings, is glued on the head as
well as the tail of the textblock's spine. Modern headbands
imitate the sewn-on headbands that functioned to protect the head and tail of
early bindings.
The Headcap is the top edge of the cover's spine that runs
parallel to the top headband. See also tailcap.
The Hinge is the flexible part of the cover on which the boards
flex open. See also inner hinge and outer hinge.
To Hinge-In a leaf or a group of leaves a strip of Japanese
tissue or linen tape is adhered along the binding edge of the leaf (or
leaves) so that the strip extends beyond the binding edge. This can then be
attached to the textblock by pasting up the part of the strip that
extends beyond the leaf (or leaves), and adhering the strip to the binding edge
of a leaf in the textblock.
A Hollow is that part or space of a case binding between the textblock
spine and the inside of the cover spine.
An Inner Hinge is the groove lying between a paste-down and
a flyleaf where the textblock is attached to its cover.
Also called a front hinge and inner joint, this serves as the functional part
of the book that
allows the covers to be opened and closed.
Interleaving is the act of placing barrier sheets of acid-free or
buffered paper between leaves or documents to prevent the transfer of media,
acids, or damaging gases from one material to another.
Japanese Tissue is a soft, strong, long-fibered, and often translucent
paper made from the fibers of a variety of plants common to Japan, especially
the
mulberry. It is available in a variety of thicknesses and colors. It is a very
versatile paper, and according to the thickness used, it can be employed for
mending torn paper, for overall lining of leaves as a reinforcement, for
reinforcing the folds of signatures, for reinforcing fragile
cloth spines,
or for mending inner or outer hinges.
Kraft Paper is a strong brown machine-made paper widely used for wrapping
purposes, and in publisher's bindings for lining the inside cover spine
(spine strip) of a case-bound book.
A Leaf is a single sheet of paper or half of a folded sheet of paper.
Leaf Attachment is the structural method used to hold the pages of
a
volume together - creating a textblock. Some leaf attachment methods
only employ dhesive to hold the pages together. Other methods employ thread
that is
used to sew together the pages of the text block.
Leather has been used as a book covering material for many centuries.
There are many different methods by which animal hides are tanned or tawed to
produce leather, resulting in a wide variety of strengths and aging properties.
Lignin is a component of woody plant fibers used to make most modern
papers (not present in 100% cotton or linen paper). Its presence in paper
contributes to chemical degradation of the paper.
The term Lignin Free refers to paper that contains no lignin.
It may be 100% cotton or linen fibers or be chemically processed to remove the
lignin from the wood pulp.
A Margin is the space around the edges of a page outside the printed
or written matter. The four margins are commonly designated as: top margin;
bottom margin; fore edge or outer margin; and inner or gutter margin.
Milling is a method used by library binders to remove old leaf
attachments and prepare a text block for double-fan adhesive
binding or oversewing. The milling machine clamps the textblock,
spine down, and moves it over a series of rotating blades that cut away
approximately 1/32 to 1/16 inch of the binding margin, thus removing old
adhesive, thread, staples, and/or the folds of signatures. After milling, a text
block is comprised of loose leaves.
Molds are microscopic fungal organisms that form masses on the surface of
paper, book cloth, or leather. Molds can appear black, white or
brightly colored and can range from dry and powdery to wet and slimy. Molds
permanently deform the surfaces they inhabit.
A Mylar Laminate Cover is a covering material made by sandwiching the
original paper cover from a paper-bound volume, or the dust jacket from a
hard-bound volume, in between a laminate of polyethylene plastic and paper. This
laminate is then used in the place of buckram to make the new cover. This
product was developed to allow libraries to retain the original artwork or text
found on paper-bound volumes or dust jackets.
Notching is a method for preparing the spine of a textblock
for adhesive binding. The binder will cut very shallow, notches into the spine
before applying the adhesive. These notches allow the adhesive to penetrate into
the pages which greatly increases the strength of the leaf attachment.
The Outer Hinge is the flexible groove of covering material on the
outside of a book on which the cover board opens. Also called the outer
joint.
Oversewing is a long practiced leaf attachment method used to sew
single leaves together. This leaf attachment method was very common in
commercial binding, but has fallen out of favor in recent years except in
specific cases. Individual leaves are grouped in small (1/8") gatherings
that are side sewn together. The oversewing machine operator continuously feeds
these small gatherings into the machine which sews the gatherings together.
Oversewing can be recognized by its very inflexible spine and uneven,
tight inner margin.
The Pastedown is the half of an endsheet that is glued to the
inside of the cover board.
pH is a chemical measure of acidity or alkalinity obtained by measuring
the quantity of free hydrogen ions in a solution. The pH scale is logarithmic
(increases by multiples of 10) and runs from 0 to 14. A pH of 7.0 is neutral,
while pH higher than 7.0 is alkaline and lower than 7.0 is acidic.
Permanent Paper is a paper that withstands the effects of aging better
than ordinary paper. It is manufactured to resist chemical action from
impurities in the paper or in the atmosphere during long term storage.
Pressure Sensitive Tape is any tape made of a film carrier with
an active, pressure sensitive adhesive applied to one side. These tapes should
not be used to repair torn leaves because the adhesives discolor and stain and
are difficult or impossible to remove.
Protective Enclosures include boxes, slipcases, portfolios, or any
other container that is designed to hold and protect books, manuscripts or other
archival materials. Many commercial containers or custom-built protective
enclosures are available for a variety of materials and needs.
Polyvinyl Acetate (PVA) is an emulsion adhesive that dries quickly and is
considered permanent. It results in a very strong bond that remains flexible
over time and does not yellow.
Rag Paper is paper made from cotton or linen fibers instead of wood pulp.
Rag paper is stronger and more durable due to its chemical stability, low
acidity, and long paper fibers.
Reversability pertains to the ability to undo a treatment or process
without harming or changing the original object. Reversability is an important
principle when performing conservation treatments on items with artifactual
value.
Rounding is the process of hammering the textblock spine
into a convex shape preparatory to backing. Rounding diminishes the
effect of swelling caused by the thickness of the sewing threads or the
application of glue from an adhesive binding. It also helps to prevent the
textblock spine from falling into a concave shape after years of use or of
standing upright on a shelf.
Section: see Signature
Sewn Through Fold refers to items with signatures sewn together.
These items can be easily identified by looking for sewing thread in the inner
margin of the middle of a signature.
The Shoulder is the outer edge of the textblock spine
against which the cover board fits. The shoulder is made when a
book is rounded and backed.
Signatures are two or more sheets of paper stacked and folded as a
group.
Also called a gathering, quire, or section. A textblock is made up of
many
gathered signatures sewn together.
Spine Linings are layers of cloth and paper used for reinforcing and
stiffening the spine of the textblock. In many publisher's adhesive
bindings, linings may not be used at all; the textblock is not reinforced
and is held together simply with a layer of glue. Ideally, textblock spine
linings should reinforce the glue and help hold the sections together.
Spine is the space between the boards of a case to
accommodate the thickness of the textblock. The inside of this space is
stiffened with a spine strip, usually made of bristol. A hinge
area left on either side of the spine strip allows for the movement of the cover
boards on the shoulders of the textblock as the book is opened and used.
The outside part of the cover spine usually receives stamping for author, title,
and publisher. This term may also be used to refer to the spine-edge of an
uncased textblock.
The Square of the book is the exposed margin of the turn-in
along the interior of the case not covered by the textblock or paste-downs.
The square runs along the fore edge, top, and bottom edges of the book.
Stamping Foil is the lettering on the spine of a volume which is
stamped into the book cloth using heat and pressure to transfer color
(gold, white, or black) from a piece of carrier film to the cloth.
Stubbing is the process of adding sheets of paper to the textblock
to accommodate pockets, inserts, or gaps.
Super is an open-weave variety of coarse, sized fabric used for
reinforcing or stiffening the textblock spine of a case-bound
book. The super forms the first spine lining on the textblock. The excess (super
hinge) that extends beyond the edges of the textblock spine is used to
attach the textblock into its case. Also called mull, crash, and gauze.
The Tail of a volume is the bottom portion of the cover and text block
on which the book rests when it is on the shelf. See also head.
The Tailcap of a volume is the bottom portion of the spine. See also headcap.
The Text Block is the main block of gatherings or leaves,
including endsheets and spine linings, which is bound together and
then attached to the case. Also called the book block.
Tide Lines are irregular lines or blemishes caused by the movement of
water or any other liquid through paper and the residual stains left behind as
the liquid dries.
Tip-in, tipped-in, tipping-in is the attachment of one leaf to
another in a book at or near the inner margin by means of a narrow strip
of adhesive along the gutter edge of the sheet.
A turn-in is the part of the covering material that is turned over the
outer edges of the boards (and spine strip) from the outside to the inside. Also
called a turn-over or overlap.
Sources:
Jane Gammon. Conservation Information Sheet Number 1: Selected Glossary of
Conservation and Preservation Terms