WATER-MARKS AND VARIETIES OF PAPER
♦Importance of water-marks♦
Though the water-mark in a sheet of paper may at first thought seem
a comparatively unimportant detail, the story of water-marks and
the part they have played in momentous transactions would easily
furnish material for a volume. Especially is this true of the early
water-marks, with which there is connected much interesting history.
They have even become important witnesses in the courts of justice,
where their silent but eloquent testimony has brought confusion to
seemingly clever criminals. The proof of the time when a water-mark
was introduced has been the means of fixing the crime of forgery,
where the forger, in order to reach the end sought through the forged
document, dated the same back, and unconsciously used a paper bearing
a water-mark of a later date. As the early water-marks have suggested
the names of many varieties of paper, the two subjects are fittingly
coupled.
It is not known exactly how long a history the water-mark has; the
first evidence of one, in the form of a ram’s horn, is said to have
been found in a book of accounts in 1330. Simple designs of common
objects, such as a pot, urn, or jug, were popular forms of the
water-mark in early days. Mention has already been made of Henry VIII.
and the curious method he adopted of showing his contempt for the
Pope, by having his paper marked with a hog wearing a miter. ♦Origin
of “fool’s cap”♦ Then followed the coat-of-arms of the king, and when
Charles I. was driven from the throne and beheaded, the “fool’s cap”
and bells was in derision substituted for the royal arms, followed
later by the figure of Britannia. Changing water-marks in those days
meant stirring history. “Pot” paper had a tankard for its water-mark,
and the “fool’s cap” gave its name to a larger sized paper, which has
borne the name to the present day. “Post” was the old size made for
letters, and bore a “post-horn” as its water-mark, the name being
preserved to-day in the United States by “folio-post.” “Crown” paper,
as its name suggests, bore the water-mark of a crown.
In recent years, water-marks have been used as a means of designating
the manufacturer, rather than for the purpose of distinguishing the
paper itself. The crane, for instance, appropriately designates the
paper made by the Cranes, a family whose name has been long and
prominently associated with the industry in this country.
♦Paper in the mechanical arts♦
The many and divers uses to which the paper product can be put have
opened up a practically unlimited field to the originality and genius
of the paper manufacturer, who has learned to so manipulate his raw
materials as to permit of the finished product’s being substituted
for iron, lumber, cloth, etc., and in many cases it better serves the
desired purpose.
As has already been stated, paper, considered in reference to its
general quality and the method of manufacture, falls into three main
divisions, viz., writing, print, and wrapping papers, but these
divisions give only an inadequate idea of the many varieties. The most
of these are obtained by the varying manipulations of paper already
complete in one or another of the three forms. The various kinds of
boards furnish an interesting example of one of the most comprehensive
classes of paper. Bristol board, so named from the place where it was
first manufactured, cardboard, pressboard, binder’s board, trunk-board,
and the like, all hold very prominent positions in this, one of the
most important of industries. The heavier of these boards are made by
combining as many sheets of paper as are necessary to give the desired
thickness, and then by using paste or applying hydraulic pressure,
consolidating them. The number of sheets used is indicated by the word
“ply,” used as a suffix, as two-ply, three-ply, four-ply, and so on.
Like other articles of the commercial world, papers take their
names from varying circumstances, and there is a large class whose
designations have been derived from the materials or processes employed
in their manufacture, as well as from the purposes for which they are
to be used.
♦Coated paper♦
Coated paper, or paper having an enameled surface, is made by applying
a mixture of clay and glue to ordinary paper. When referred to in
connection with coated paper, this ordinary paper is called raw stock
or body paper. It is manufactured in the regular way, but is made
slack-sized and sent to the coating factory in web or roll form, and
before it has been calendered. The clay used is pure kaolin or china
clay, formed by the disintegration of feldspathic rock. The clay is
largely found near Cornwall, England, and the pure white variety,
principally used, is known as leemore clay, while the finest is called
blanc fixe. The clay is ground to the fineness of fine wheat flour and
mixed into solution of about the consistency of milk. Its purpose in
the paper-coating process is to cover the body paper, giving it an even
surface, susceptible of a high and glossy finish. The glue used is of
the ordinary sort so well known in the regular market. Its presence
renders the clay solution very adhesive when applied to the body paper.
♦Extreme smoothness required♦
The cost of illustrations having been greatly reduced through the
perfection of photogravure or half-tone processes, a large and
increasing demand exists for a paper of extremely smooth, firm,
and sensitive surface, suitable for the reproduction of the finest
half-tone cuts; a paper with such delicate fineness and susceptibility
that the minute lines of a photogravure cut--so minute in instances as
to be indistinguishable to the touch of the finger--will be perfectly
reproduced when printed upon its enameled surface.
Large factories are devoted entirely to the coating process. They do
not necessarily make their own body paper, but frequently purchase it
from outside sources. At first, this clay solution was carried to and
spread upon the surface of paper by the use of a fine hair brush. This
was applied to one side or surface of the paper at a time, the same
process being repeated on the opposite side, if both were to be coated.
Since its earlier introduction, the process of surface-coating paper
has undergone great improvement, and the method to-day in vogue, while
seemingly complete and exceedingly rapid, is yet readily understood,
and the machinery required is quite simple. This consists of:
♦Parts of coating machine♦
First--A vat, to hold the enameling solution.
Second--Rollers, to regulate its distribution upon the web of paper.
Third--Brushes, to work out small lumpy particles and overcome any
tendency to unevenness of coating.
Fourth--An automatic carrier, to convey the coated web through a
drying-room; after which it is calendered to the surface wanted and cut
into sizes required.
A roll of body paper ready to be enameled is placed before the vat
which contains the coating solution. The end of the paper-web is
started through the solution by being passed under a wooden roller hung
in the vat--the purpose of the roller is to insure an even tension
and uniform immersion of the web. After passing under the roller the
paper-web leaves the vat, and is passed between two rollers that
regulate the thickness of the coating and remove all surplus. From the
rollers the web passes forward through two sets of brushes, one above
and one below, both sets working back and forth transversely upon the
top and bottom of the coated web. ♦Distribution of coating♦ Each set
of brushes is comprised, first, of a coarse, then intermediate, and
finally of extremely delicate brushes, made usually of camel’s hair,
which as they play upon the coated surface work out all roughness or
small lumpy particles, and reduce the coating to uniform fineness.
♦Carrier♦ Upon leaving the brushes, the paper reaches an automatic
carrier. This consists of wooden slats conveyed at intervals upon two
endless chains that pass at either side of the machine just outside
of the coated web, the chains supporting the slats at their ends. As
the paper reaches the slats it falls upon one, which by an ingenious
device is carried forward and upward, permitting the coated web of damp
paper to fall in long loops or folds--succeeding slats follow upon the
carrier at regular intervals, and prevent any marring of the damp
surface by keeping it from foreign contact. The slats upon the carrier
convey the web in this festooned form through a drying-room, kept at
a temperature of about 140° Fahrenheit, thus thoroughly drying the
coated web. The paper, dried by its passage through the drying-room,
is rerolled upon reels, and is then finished by being passed rapidly
between alternate steel and paper rollers, after the ordinary method of
calendering paper. ♦The gloss or finish♦ The rollers are susceptible
to regulation or adjustment, so that almost any degree of gloss can be
put upon the coated surface; hence, for the highest finished paper the
rolls are set slightly closer together, giving greater pressure; and
if necessary, the web can be run through a second or third time. After
calendering, the paper is cut to sizes required, this being done in the
same manner all rolled paper is cut into sheets, except that if three
or four rolls are run through the cutter at once--as is frequently the
case to facilitate rapid cutting--a device is used that causes the
sheets from each roll to fall in separate piles, so that all of the
sheets in each pile will be from one roll, insuring uniformity.
[Illustration: THE SUPERCALENDERS--PAGE 82]
The quality and value of coated paper depend upon the quality of the
body paper, the fineness of the clay and other ingredients used in
the coating, together with the perfection of its manufacture.
♦Glazing processes♦
Glazed paper is one of the most interesting and useful forms of coated
paper. The glazing is done by two processes, known as friction and
flint glazing. In either process the method of coating, up to and
including the drying, is practically the same as that followed in the
coating of other papers, except that wax is mixed with the coating
to act as a lubricator, and to permit of securing the desired glassy
finish.
In friction-glazing, the paper is passed through a friction calender,
which consists of a cotton roll and a chilled iron roll, the latter
revolving at much greater speed than the former, the friction generated
giving the paper a very high polish.
In the flint process, the paper is fed into a special burnishing
machine, and passes over a groove in which operates a flint-stone,
fitting closely in the groove and working back and forth upon and
across the sheet. As will readily be seen, this is a very slow process
as well as expensive, although it produces a finish, higher and more
lasting, than can be secured by the friction method.
Paper made by the two processes can be distinguished by the lines
appearing on the flint-paper made by the stone in its travels across
the sheet.
Glazed papers are used largely in the manufacture of boxes and numerous
fancy articles.
♦Lithographic stock♦
Lithographic paper is a product especially prepared to take impressions
from stones in lithographing. For ordinary use, common book or
print papers are employed, but these are usually given extra care
and attention in the course of their manufacture; the stock is so
manipulated as to not only secure the desired quality and finish, but
also to counteract the tendency of the paper to stretch, which if not
overcome is apt to destroy the register and injuriously affect the
quality of the work. The better grades of lithographing-paper are made
by applying a clay coating especially prepared to bring about the
desired results.
Asbestos-paper is made by combining paper pulp and the mineral
amianthus. Its fireproof and non-conducting qualities make it a staple
commodity for many purposes, such as drop-curtains for theaters,
insulation of electric wires, packing of steam-pipes, etc.
Tar-paper is a coarse, thick paper soaked with a tar product, and used
for covering roofs and lining walls, to secure warmth and dryness.
Paper coated with the white of eggs is known as albumen-paper, and is
employed as a vehicle for silver prints in photography.
♦Photographic♦
Paper which has been so chemically treated that the color of its
surface may be altered by the action of light is known as sensitized
paper. Under this general designation are included numerous papers
differing from each other in the details of manufacture, though the
name is most commonly applied to paper that has been floated in a bath
of nitrate of silver, or coated with an emulsion of silver-nitrate of
chloride. ♦For blue-prints♦ One of the most common of papers included
under the general term is that known in general trade as blue-process
paper, which is prepared by floating white paper in a solution of
potassium ferrocyanide. It is used for copying plans and maps, as well
as for printing photographic negatives. After exposure to the light
for the proper length of time, under the subject to be reproduced,
the print is finished by immersion in several changes of clean water.
Very similar to the blue-process paper is the blue or ferro-prussiate
paper, which is sensitized or made sensitive by being treated with a
solution in water of red prussiate of potash and peroxide of iron.
This may be applied as a coating to the surface of the paper, or the
latter may be floated upon the solution. When exposed to light under a
drawing, those parts of the sheet to which the light has access through
the transparent portions of the drawing are more or less affected,
according to the greater or less transparency, as well as to the length
of the exposure. When this printing has proceeded as far as desired,
the sheet is washed in clear water, and those parts that have been
protected from the light, become white, while those exposed to the
light and affected by it take on, when dry, a permanent blue.
♦Other sensitized papers♦
Another variety of what may properly be termed sensitized paper is the
arrowroot-paper used in photography for positive prints. It is plain
or non-glossy, and is coated with a weak solution of arrowroot in
water, with sodium, chloride, and a trace of citric acid. Photographic
paper, as such, includes a great variety of these sensitized papers,
employed in various processes of the art; albumenized, salted, coated
with emulsion, or otherwise treated. One of these, known as Pizzighelli
paper, a sensitized platinum-paper, gives a neat surface, and soft,
clear, gray tones, which are most artistic and pleasing for many
subjects.
♦Carbon or transfer♦
Other papers are so treated chemically as to produce certain effects
under the application of pressure, instead of by the action of light.
Such is the transfer-paper used for transferring a design mechanically,
which is prepared by coating the sheet with adhesive pigments of
lampblack, vermilion, indigo, or other chemical. The carbon-paper
universally used in typewriting when more than one copy of a letter or
paper is desired, is paper faced with carbon or lampblack. Alternate
sheets of writing and carbon paper, placed one above the other, are put
into the typewriter, and the impression of the letter on the surface of
one sheet serves to print three or four sheets underneath.
♦Manifold♦
Manifold writing or copying papers are made from strong unsized papers
adapted to receive writing or printing, and to transfer this readily
under pressure to another sheet which has been dampened. It is the
common rule to-day to make permanent record of correspondence and
business transactions by the use of this system of impression-copying.
The manifold paper largely used by railroads is very thin, making
possible a large number of copies from a single impression, thus
effecting a great saving of time and labor.
♦Stencil♦
Stencil-paper is produced by giving to a sheet of fibrous paper, as
fine and thin as gauze, a thick, even coating of paraffin, and from
this the stencil may be prepared in two different ways. Either it may
be placed in the typewriter, from which the ink-pad or ribbon has
been removed, and the stencil cut by allowing the type to strike the
wax sheet, or it may be placed upon a flat steel plate, the surface
of which is cut into multitudinous microscopic steel points, and then
written upon by a stylus, a steel pencil made especially for the
purpose, which cuts the wax without tearing the gauzy body of the
sheet. Copies are produced in the same manner as with other stencils,
viz., by placing the blank sheet under the stencil and then passing an
inked roller over the latter.
Luminous paper is prepared by compounding the pulp with gelatine and
phosphorescent powder.
♦Transparent paper♦
Transparent papers are made by several different methods. The usual one
employed is to apply a thin coating of a solution of Canada balsam in
turpentine, or a solution of castor or linseed oil in absolute alcohol,
the alcohol in the latter case being permitted to evaporate, thereby
rendering the paper transparent. Such paper is largely used for tracing
purposes, and may be restored to its original state of opacity, with
the tracings left unchanged, by removing the oil with a fresh bath of
alcohol.
♦Safety♦
Safety-paper is a paper so treated or coated with chemicals that any
ink-writing upon its surface cannot be erased, effaced, or removed
without leaving indelible marks on the paper. As its name implies, it
is used for safety in bank-checks or other commercial paper, to protect
against alteration.
Gunpowder-paper is prepared by spreading an explosive substance on
paper, which is then dried and rolled up in the form of a cartridge.
♦Sand and emery♦
Sand and emery papers are produced by coating a stout paper with glue,
and then sprinkling sand or emery-dust upon the surface. Man’s skill
has devised for this purpose an ingenious machine. This first coats the
paper with glue from a revolving brush, which plays over the surface
of melted glue in a steam gluing-pot below. Having accomplished this
result, it softens the glue with a spray of steam, and sifts the sand
upon the surface, all surplus sand dropping into a box below as the
sanded or emery-surfaced paper passes over a roller. Other loose
particles are blown off by a fan, while the remaining ones are still
more firmly fixed by a second jet of steam.
♦Cork♦
Cork-paper, an American invention, is made by coating one side of a
thick, soft and flexible paper with a preparation of glue, gelatine,
and molasses, and covering it with finely ground cork lightly rolled
in. This paper is used for packing bottles, glassware, etc.
♦Slate♦
Slate-paper, which takes its name from the fact that it can be cleansed
like a slate, is prepared from the regular product, of the required
thickness and consistency, by the use of benzine, followed by a
preparation made of lead, zinc oxide, turpentine, seed-oil, copal, and
sandarach.
Soft plate-paper is a thick unsized paper, especially adapted to
receive impressions for fine engravings printed from steel and other
plates.
♦Filter♦
Filtering-paper, much used by chemists and druggists, is simply unsized
open or porous paper. With such paper, of course, the process of
manufacture ceases at the first drying or crushing rollers, all the
finishing or hardening operations being omitted.
[Illustration: CUTTING FROM THE ROLL--PAGE 82]
♦Waterproof♦
Waterproof papers comprise a large and most useful class. It is
practically only within the past twenty-five years that a process
has been known and employed for rendering a paper waterproof by
destroying its absorptive properties. At the present time there are
many and various methods used in waterproofing, such as soaking the
stock in dissolved shellac and borax. This method is found especially
satisfactory in waterproofing heavy paper and boards. Another process
is by brushing the surface of the paper with boiled oil, and paper thus
prepared was formerly used largely in lieu of bladders and gut-skins
for wrapping butter, covering fruit-jars, etc., but it has been almost
entirely superseded by the introduction of parchment-paper, of which
mention will be made later.
♦Paraffin♦
Since the invention of the process of clay-coating paper, it has been
found possible to incorporate in the coating solution certain materials
which render it waterproof. The application of wax or paraffin to paper
to make it waterproof is a common method; and although this product is
largely used, the process has never reached the state of development
expected. A great amount of time and money has been spent in the
endeavor to perfect the process, and at the same time cheapen the
cost, but so far with only indifferent success, and the experiment has
usually proved very discouraging and expensive to its supporters.
In its simplest form, this method consists in dipping the paper in a
bath of melted paraffin, the paper being at a temperature lower than
the melting-point of the paraffin, and promptly removing it from the
bath, whereby the adhering paraffin is prevented from entering the
paper to any considerable extent, and forms a thin coating upon its
surface. This paper is odorless, and is used for wrapping meats, fish,
butter, candies, etc.
♦Vegetable parchment♦
Parchment-paper, which is almost like the real parchment made from the
skins of animals, is prepared from unsized rag-paper by immersing it
for a few seconds in a solution of two parts of sulphuric acid, or oil
of vitriol, in one part of water, at a temperature of 60° Fahrenheit,
then washing it in cold water and removing any remaining traces of the
acid by dipping it in a weak solution of ammonia. By this treatment
it is rendered tough, translucent, glossy, and almost impervious to
water. It is known as vegetable parchment, and is extensively used in
wrapping lard, butter, meats, etc., and also to hermetically seal jars
and pots for preserving fruit.
♦Grass-bleached♦
Silver tissue, or what is known to the trade as grass-bleached tissue,
is extensively used for wrapping silverware. It is specially treated to
remove all chemicals that would tend to corrode or tarnish silver. The
best qualities of this paper are made in England.
Metallic paper is paper washed with a solution of whiting, lime, and
zinc. Characters written on this paper with a pewter pencil are almost
indelible.
♦Litmus♦
Test or litmus papers are used in laboratories and factories for
indicating the presence of acids or alkalies and various liquids. It
is prepared by treatment with a peculiar coloring matter that gives
its name to the paper. It is of a blue or yellow tint, according to
the chemical employed in its preparation, and changes color under the
influence of different chemical agents. The blue litmus paper, for
instance, when thrust into an acid solution becomes red, but may be
restored to its normal color by being subjected to the action of an
alkali.
The enumeration already given by no means exhausts the uses of the
wonderful product evolved and perfected by centuries of study and
toil. Widespread as is its use in the various departments of chemistry,
and in all the graphic arts, it fills an equally wide field of
usefulness in the mechanic arts, where it has become a staple.
♦Paper car-wheels♦
One of its most curious uses in this field is in the manufacture of
car-wheels. The material is calendered rye-straw board, or thick
paper, and the credit of the invention belongs to Richard N. Allen,
a locomotive engineer. The paper is sent to the car-wheel shops in
circular sheets measuring from twenty-two to forty inches in diameter,
and over each of these is spread an even coating of flour paste. The
sheets are then placed one above the other until a dozen are pasted
together, when all are subjected to a hydraulic pressure of five
hundred tons or more. After two hours’ pressure, these twelve-sheet
blocks of paper are kept for a whole week in a drying-room heated to
a temperature of 120° Fahrenheit, after which a number are pasted
together, pressed, and dried for a second week; a third combining of
layers is then made, followed by a month’s drying, until there is
obtained a solid block, containing from one hundred and twenty to one
hundred and sixty thicknesses or sheets of the original paper. The
thickness is only from four and one-half to five and one-half inches,
and in weight, density, and solidity the block resembles more the
finest grained, heaviest metal than it does the original paper product.
It may be called car-wheel paper. To complete the wheel, there are
required a steel tire, a cast-iron hub, wrought-iron plates to protect
the paper on either side, and two circles of bolts, one set passing
through the flange of the tire, the other through the flange of the
hub, and both sets through the paper. The paper blocks are turned on a
lathe, which also reams out the center-hole for the hub; two coats of
paint are applied to keep out moisture; the cast-iron hub is pressed
through by hydraulic pressure; the other parts are forced into place,
and the paper center is forced into the steel tire by like hydraulic
power; and there, a product of human ingenuity, is a paper car-wheel,
which never is injured by vibrations, and is safer and longer-lived,
though costing more, than any other car-wheel made.
♦Paper lumber♦
Paper lumber is another curious form of the staple. It is produced
by making the ordinary strawboard on a cylinder machine, running it
through a vat of resin and other waterproofing heated to a temperature
of 350° Fahrenheit, then placing together the sheets so resined and
subjecting them to hydraulic pressure. The result is a paper board
three-sixteenths of an inch thick, and of a dark or blackish color.
It can be cut with a saw or chisel, is very hard and solid, and has
been marketed in slabs thirty-two inches in width by twelve feet in
length at forty dollars a thousand. It is used for the interiors of
railway-cars and for perforated chairs.
♦Chamois fiber♦
A product of the paper-mill has been used quite extensively the last
few years for clothing. It is called chamois fiber or mangled fiber.
It is made from a long-fibered, strong sulphite stock, and is passed
through a specially constructed machine which mangles or crushes the
fiber, giving it a soft and flexible character, like chamois. It
has been used in dress-skirts and for under-vests, and has an added
advantage over cloth in being practically impervious to air.
Paper boats are made of especially prepared paper pulp, molded and
pressed into shape.
Paper flour-barrels, water-pails, and other like articles are made by
stamping out their form from paper pulp or heavy cylinder-made paper
possessing folding properties.
♦Papier-maché♦
Papier-maché is another product of paper almost unlimited in its uses.
The materials of which it is made, for the commoner classes of work,
are old waste and scrap paper, repulped and mixed with a strong size
of glue and paste. To this are often added quantities of ground chalk,
clay, and lime. For the finest class of work, a method invented in 1772
by Henry Clay, of Birmingham, England, is followed. Sheets of specially
made paper are soaked together in a strong size of paste and glue,
molded into the desired shape and dried in an oven, other layers being
added, if necessary, to secure the required size and shape. The dried
object is hardened by being dipped in oil, and is then trimmed and
prepared for japanning and ornamentation. In delicate relief-work, a
pulp is prepared of scrap paper, which is dried, then ground to powder
and mixed with paste and a proportion of potash until a very fine, thin
paste is formed. Papier-maché is an exceedingly strong, tough, durable
substance, slightly elastic, and not liable to warp or fracture. The
articles for which it is used make a long list, including ornamental
boxes, trays, match-safes, dolls’ heads, toys, anatomical and botanical
models, artists’ lay-figures, picture-frames, panels, and other mural
ornaments. It has also been employed in the construction of coaches
and for door-panels, while under the name of carton pierre, which is
practically the same substance, are molded ornaments for walls and
ceilings. Ordinary roofing and carpet felts are similar in manufacture.
The use of moistened papier-maché in electrotyping, and the method
followed, is too well known to need description.
♦Wall-paper♦
In the use of paper for wall-hangings, the artistic and practical come
together. From the earliest days when men made for themselves permanent
abodes, mural decoration of one form or another has been known, and
every branch of painting, sculpture, and decorative art has been called
into service. It is not strange that paper, with its many adaptations
and wonderful possibilities, should, when it reached the proper stage
of development, find one of its principal uses in making beautiful
the walls of our homes. The eighteenth century was well advanced when
wall-papers came into use in Europe, but it is claimed that they were
used much earlier by the Chinese, who, with characteristic ingenuity,
have made clothing, handkerchiefs, napkins, and a great variety of
other useful articles out of paper. The first patterns were very
crude, but through the slow processes of development and improvement
a wonderful degree of perfection has been attained. Beauty and taste
in the decorative art find their highest exponent in the “repped
morocco” and fine colored papers. Repped or corded papers are those
having raised designs, which are produced by passing the web between
rollers on which the ribs or other devices have been cut or engraved.
The embossing of morocco and other paper of raised design is done
in the same way. The morocco and leather papers are imitations of
the old stamped leather hangings of earlier days, which were usually
made of the skins of goats and calves, cut into rectangular shape.
♦Embossed effects♦ These skins were stamped and embossed, having been
first covered with silver-leaf and varnished with a transparent yellow
lacquer that gave to the silver the appearance of gold. The reliefs
were painted by hand in many bright colors. Leather wall-papers are
treated in a similar manner, and are capable of being brought to any
desired degree of richness. The richer grades of flat-surfaced figured
wall-papers are printed with wooden blocks, upon which the designs are
cut in relief, there being a block for each color. These blocks are
applied by hand, after having been dipped in an elastic cloth sieve
charged with tempera pigments. Care is used to place each block on
exactly the right place, thus securing perfect register. In many cases
the figures on the block are inlaid with copper, especially in the thin
outlines. ♦Block printing♦ In “block” and gold and silver printing the
design is first printed in a strong size; the finely cut wool of the
required color, called “flock,” or the metallic powder imitating gold
or silver, is then sprinkled on by hand all over the paper, and adheres
closely to the size. Where the pattern is to stand out in relief,
the process is repeated until the desired results are obtained. The
cheaper sorts of wall-papers, as well as some that are very rich, are
printed by machinery from the web, on rollers or cylinders carrying the
designs, under which the paper passes.
♦Surface tinting♦
Reference has been made to the process of coloring paper by mixing
the colors in the engine, but wall-papers and many others are
surface-tinted by being run through a color-vat. An iridescent or
“rainbow” surface is given by treating the paper with a wash containing
sulphates of iron and of indigo, and then exposing quickly to
ammoniacal vapors.
[Illustration: SORTING OF FINISHED SHEETS--PAGE 83]
Mother-of-pearl paper is produced by a somewhat similar process.
Glazed paper is first floated on a solution of silver, lead, or other
metal, then, when dry, exposed to the vapors of sulphide of hydrogen,
after which collodion is poured over the surface, producing rich and
fascinating color effects.
♦Marbled paper♦
Marbled paper, used largely in binding, is prepared from a shallow bath
of gum tragacanth, or goat’s-horn, upon which the workmen sprinkle from
a flat brush the films of colors needed for the desired pattern. When
the whole surface is covered with bands and splashes of color, the
workman takes a huge comb, which he draws with a wavy motion the length
of the tub. The practiced marbler will so lay the colors and manipulate
the comb as to copy any desired pattern. The marbling is done by deftly
laying the smooth white paper on the bath for a moment, and then
removing it, when the entire film of color comes with the sheet, so
that a resprinkling of the bath is necessary. In marbling the edges of
the leaves of a book, the body of the book, without the covers, is so
held that the edges may be quickly dipped into the bath. In this case,
of course, one covering of coloring matter will marble a number of
volumes. Paper is also colored, as has been noted, by passing the web
through a coloring-bath.
The papers briefly described in this chapter have been classified
largely according to the methods of manufacture or chemical treatment,
or to the purposes for which they were to be used. Another basis for
classification is found in the size. In the United States, the usual
writing papers of commerce are divided, according to sizes, as follows:
♦Sizes of writing paper♦
Commercial note 5 × 8
Letter 8 × 10
Flat cap 14 × 17
Crown cap 15 × 19
Demy 16 × 21
Folio post 17 × 22
Double cap 17 × 28
Medium 18 × 23
Royal 19 × 24
Super royal 20 × 28
Double demy 21 × 32
Double folio 22 × 34
Double medium 23 × 36
Imperial 23 × 31
Elephant 23 × 28
Double royal 24 × 38
Columbier 23 × 34
Atlas 26 × 33
Antiquarian 31 × 53