=Paper and Paper Making=
Much of the paper used in books today is made of wood. Wood is
converted into paper-making material in three ways. In one, it is cut
into convenient lengths, stripped of its bark and finely ground on
grindstones, and bleached. The product is called ground wood pulp.
The paper made from this pulp is hastily and cheaply put together,
has little strength, and soon turns yellow and grows brittle. There
is often added to ground wood before making it into paper, more or
less sulphite or soda pulp, usually the latter, the product of another
process of turning wood into paper-making material.
In the sulphite and soda processes the wood is freed of bark, cut into
small pieces, and reduced to a pulp by being heated with water and
chemicals under pressure in an air-tight steel tank or boiler. Sulphite
and soda pulp, which get their names from chemicals used in reducing
the wood to pulp, have longer and better fiber than ground wood pulp.
In both processes certain means are used to whiten the fiber and free
it from sap, gum, and other things which would prevent it from acting
properly in the paper-making machine, or would tend to make it grow
yellow or spotted. Spruce or basswood are the woods chiefly used, and
they seem to submit themselves to treatment better and to give a longer
fiber than other kinds. The pulp made from rags is often mixed with
sulphite and soda pulp. The rag-pulp fiber improves the quality of the
resulting paper for reasons not easily set forth. Paper made entirely
of wood may be of good quality, especially sulphite papers. The popular
outcry against wood paper is based on the fact that much of it is made
very cheaply and poorly.
The rags used in paper making are nearly all cotton. They are not
all of them rags in the ordinary sense of the term. Many of them are
cuttings from clothing factories and have never been used. New rags do
not act the same way under the treatment which changes them to paper
pulp as do the old ones. The paper made entirely from new cloth differs
somewhat from that made from old rags. The best book papers, however,
contain only stock prepared from old rags.
The process of changing rags into paper is very similar to that of
changing wood into paper. The rags are cleaned, freed from foreign
substances, cut into small pieces, thoroughly washed, bleached, and
then beaten to a pulp, under water, by machines which convert them into
a soft, homogeneous, creamy mass, called technically stuff, and yet
preserve the greatest possible length of fiber. This process of beating
rags into good paper-making material requires care and considerable
time. If the process is hastened unduly the resulting material is not
so good.
Paper is made from other materials besides wood and cotton; but nearly
all of that used in books in this country is made of one or other of
these two materials, or of a combination of the two.
The stuff produced as described, almost milk-like in its consistency,
is pumped from a tank, in which it is kept constantly stirred to
prevent the fiber from settling, onto the paper-making machine. This
machine is an evolution from a simple hand appliance which was used by
paper makers for several centuries. It was a shallow tray with a bottom
made of a network of wires. This was held in the hands, dipped into a
vat containing the paper-making material, and as much of the latter
taken up on the wires as in the judgment of the maker was sufficient
for a sheet of paper. It was then shaken gently, and deftly handled,
until the water, running through the wires, left on the latter, and
spread evenly over them, a layer of fibers. These dried and matted
together in a few seconds sufficiently to enable the maker to turn them
out on a blanket; on this another blanket was spread, and on this was
laid another layer of fibers. The skilful maker of paper by hand (in
a few places in this country the craft is still practiced) can secure
considerable evenness in the layers of fiber or pulp on the wire of his
frame; but the layer is never of quite the same thickness throughout.
Handmade paper can sometimes be distinguished by these variations in
its thickness. Machine-made paper is of nearly uniform thickness. In
the process of taking up from the vat by hand a thin layer of stuff,
the maker wove together the fibers in every direction by skilful
and delicate movements of the frame. A paper-making machine cannot
so thoroughly interweave the fibers. Paper made by hand, therefore,
has a quality which cannot be secured on a machine. This peculiar
texture of handmade paper of the first class delights the connoisseur,
and furnishes a printing surface superior, in some respects, to any
machine-made paper.
The paper-making machine consists primarily of an endless roll of
wire screen, similar to that forming the bottom of the shallow tray
used in making paper by hand. This wire screen, stretched around
rollers, travels almost horizontally away from a broad shelf from
which it receives a stream of stuff pumped onto the latter from the
tank before mentioned. As the pulp pours out onto this wire it settles
over the screen, and is woven together by the latter's oscillating
and forward movement, and by the time it reaches the end of the
screen is sufficiently matted and dry to hold its shape, the water
being removed by suction. It is then picked up by a roller, and goes
through a succession of rolls, varying in size, number, character, heat
and pressure, according to the quality of the paper being made and
the surface desired thereon. In some cases, toward the close of the
process, it is passed through a tank containing a thin mixture of glue
and water, called size, and then is again dried. Coming out as paper at
the end it is cut into lengths and piled, or gathered on a roll.
The wire diaphragm onto which the paper pulp first pours, and during
the passage over which it is worked into a mat, the water meanwhile
being extracted from it, is of varying styles. If perfectly plain the
resulting paper is almost without marks, and is said to be wove. If
made of wires of different sizes properly arranged the paper, as it
lies on it, receives deeper impressions from the larger wires than from
the smaller and the former appear as light lines running through it
when finished. Paper thus marked is called laid, to distinguish it from
the wove. As the paper comes from the wires it passes under the dandy
roll. This roll sometimes has figures or letters raised on its surface.
These impress themselves on the soft paper and produce a greater
transparency where they touch, sometimes reducing the thickness, and
give the finished paper what is called a watermark. It is so called not
because it is made of water or by water, but because it looks as though
it were drawn on the paper with a point dipped in water.
Endless varieties of paper can be made from the same materials. It may
contain more or less rag; may be beaten to a greater or less extent
and with more or less care; may be spread thicker or thinner; may be
rolled on hot rolls, or polished, more or less; may receive more or
less sizing; may be dyed in a vat before it starts for the machine, or
dipped in dye after it is made, or color may be applied to one surface
by machine. The fiber may be carelessly produced, and the chemicals
used in bleaching and cleaning it may be only partially neutralized,
with the result that the paper will soon act as if being eaten with
acid, and will rapidly turn yellow under a bright light.
The ordinary observer can distinguish between very poor and fairly good
paper in books. He cannot distinguish between paper of fairly good
quality and the best.
The paper used in newspapers is nearly all made entirely of ground
wood. Most of it is made as cheaply as possible, and soon grows brittle
and dark in color. This is of little consequence in most cases. For the
ordinary newspaper the paper has served its purpose if it looks well
for twenty-four hours after it is printed and exposed to the light.
Books are generally printed on paper which has not been very highly
polished. Ink is taken from the type more readily by paper of this
kind, especially if the latter be rather soft in texture, so that the
press drives into it the face of the type bearing the ink. Modern
processes of reproducing pictures give plates for printing, many of
which are made up of very fine lines placed very closely together and
having very shallow depressions between them. To print from these
with good results the paper used must have a very smooth, highly
polished surface. The press drives soft paper down into the narrow
places between the fine lines and blurs the impression of the cut.
Newspapers which use process-cuts of the kind mentioned are obliged
to use paper with a smooth surface to get good results. This smooth
surface is generally produced, as already noted, by passing the paper
between hot metal rollers, a process called calendering. In a more
expensive process, called plating, the paper, cut into sheets, is laid
between sheets of zinc until a pile of several inches in thickness is
formed, and this pile is passed several times under rollers exerting
a heavy pressure. This smooths, polishes and hardens the paper. Much
of the paper used for illustrations in books has a surface made by
applying a coating of clay or other material to it and then polishing
it. Quite good results can be obtained with fine line cuts on
calendered or plated paper without the addition of a coating of clay.
The illustrations on coated paper which are found in books are very
commonly printed separately from the book itself, which is on ordinary
uncoated paper, and inserted separately. Generally these inserts are
not carefully fastened in and cause much annoyance by falling out after
the book has been subjected to a little use.
Recently paper makers have succeeded in producing a paper which has a
smooth surface without the high polish usually found on that which is
coated, or highly calendered. The polished surface of these papers,
especially of the coated, is very objectionable to readers, light being
reflected from it in an unpleasant way.
It will be seen from what has been said that it is difficult so to
describe what we may call good book paper that it can be readily
distinguished. Constant study and careful comparisons of the papers one
meets in books will enable one to judge of them with some success. One
who has much to do with books should take note of the paper of which
they are made, and learn to distinguish between poor and good, and the
good and the best, as far as possible. This is especially desirable
for one whose work with books includes their rebinding and repairing.
Coated paper breaks easily, the stiffening added to it by the coat of
clay giving it a tendency to fall apart as soon as it has been folded
in the same place a few times. Soft and fragile paper, such as is found
in many books, will stand very little wear at the joint in the back.
Paper not carefully bleached and freed from the chemicals used in
bleaching, rapidly discolors at the edges where exposed to light. Such
facts as these, and many others, will be found useful when one comes to
have books rebound, or attempts to repair them.
That side of the paper which touched the wires on which it is made is
different from the other. This difference is usually visible to the
trained eye. It is often taken into consideration in fine printing.
As the pulp flows out upon the wires it tends to mat together more
thoroughly along the line of flow than across it. This gives paper a
grain, along which it tears and folds more readily than across it. This
fact also is often taken advantage of in good printing.
All paper expands or stretches when wet. This is to be kept in mind in
mending books. An added strip, pasted on, usually draws and wrinkles,
when it dries, the paper to which it is applied. Hence the rule, in
mending, to use thick paste and apply the pasted sheet or strip to its
place as quickly after pasting as possible.
Mr. Chivers has recently made, 1909, with the help of chemists
and other experts, a very careful examination of the composition,
structure, tensile and folding strength and other qualities of the
paper now used in several thousand popular books. The results of
this examination, when applied to the subjects of book-selection and
book-buying, will be of great value to libraries. The quality of the
paper used in the books on which libraries spend a large per cent.
of their book fund--novels--is the question that should be first
considered in selecting editions. Libraries may hope soon to be able to
select editions much more wisely than heretofore. The investigations
by Mr. Chivers, and those carried on by U. S. Government experts
in Washington, will not only enable libraries to discover the best
editions for purchase, but will also enable them to secure bindings so
carefully adapted to the quality of the paper in each book as to give
that book the longest possible life of usefulness.