Edward A Dawe.

Paper and its uses : a treatise for printers, stationers and others online

. (page 2 of 12)
Online LibraryEdward A DawePaper and its uses : a treatise for printers, stationers and others → online text (page 2 of 12)
Font size
QR-code for this ebook

Wood, chemical or mechanical, usually finds its way
to the paper mills in the form of pulp boards, and is
known as chemical or mechanical wood pulp. No
boiling is necessary, but the boards are fed into the
breaking engine, and reduced to half-stuff, a little bleach
liquor added to chemical wood, and the contents of
the engine, when sufficiently reduced, are let down to
the draining tanks for the bleach to expend itself.
Then the pulp is ready for the beating engine, where it
is reduced to the necessary degree of fineness.

Some materials are more effectively reduced to
pulp in the edge runner or kollergang. This machine
is similar in appearance to a mortar mill, but the
arrangement is slightly different. The pan of the
machine is stationary, and the stones revolve and travel
round the pan. Only a small quantity of water is used
with the pulp, and waste papers which require rubbing
apart only, and strong, wood pulps of which the fibres
are drawn out, and not in any way reduced in length,
are treated in this machine more economically and
more effectively than in the beating engine.



ENGLISH hand-made paper is still looked upon as
the best paper obtainable. Some fourteen firms still
make paper by hand, and although the number does
not increase, there is no sign of its diminution. The
reduction of the rags to fibre was treated in the
last chapter. Before leaving the beating engine the
colouring matter is added ; in the case of a white
paper a small amount of blue is necessary to counter-
act the grey appearance which the natural pulp
usually assumes. This is merely equivalent to the
blueing which is resorted to for giving linen a bright
appearance, and is not sufficient to tint the paper. If
the paper is to be blue laid, azure, or yellow wove,
smalts is the colouring matter used. This is an in-
destructible blue, being cobalt glass reduced to ex-
tremely fine powder, and is used for the highest grades
of papers, but many hand-made papers will be found
to be coloured with ultramarine, which is a very good
blue, but not quite so durable as smalts. Coloured
papers require different additions, some in the form of
powders or dry colours, others in chemical solutions,
which by combination produce the desired colour in
the pulp. When thoroughly mixed, the pulp is let
down to the stuff chests and kept in constant motion
by revolving paddles. The vat at which the paper-


maker the vatman stands is kept supplied with
pulp, diluted to a regular consistency, kept in motion
by an agitator, and a constant temperature is main-
tained. The mould used is a wooden frame, strengthened
by ribs across its width, and a wire top of laid or
woven wire. In the case of laid papers the wires are
laid side by side, tying wires about an inch apart are
superimposed, and fastened to the laid wires by very
fine brass wire. These wires make an indelible im-
pression upon all paper made upon the mould, and
distinguish laid from wove papers, the latter being
made upon a woven wire
mould. Watermarks are
the results of designs in
reverse fastened to the
mould, the design being
formed with wire upon
the mould, or else an
electrotyped mark is sol-
dered to the mould.

FIG. 3. Hand Moulds and Deckle
(Laid and Wove Moulds).

Watermarks may be
simply small designs or
lettering, or they may

take the form of elaborate pictorial designs, but their
purpose is to add distinction to the paper, and in
some cases to prevent forgery of valuable notes or
documents. Upon the mould is laid an open frame,
known as the deckle, which serves to confine the
pulp to the mould. For all papers two moulds are
used in order to continue the cycle of operations un-

The vatman takes a mould, places the deckle upon
it, dips the mould into the vat of diluted pulp, and lifts
just the quantity of pulp necessary for the weight of
paper being made. A slight shake is given to the


mould, a small side shake and a greater shake back-
wards and forwards, something like the shake given to
a type case, but less violent, the object being to cause
the individual fibres to cross and felt together. The
mould is kept perfectly level, or the sheets are thinner
at one edge than at the others, the mould is pushed

FIG. 4. Method of Making Small Sheets on Hand Mould.

along a support by the side of the vat, the deckle
removed, and the operations of moulding repeated with
the second mould.

The coucher who places the paper upon the felts
ready for pressing, or couching, stands to the left of
and facing the vatman. He takes the mould, stands
it at an angle to drain, and places the mould face
downwards upon a felt ; the paper remains on the felt,


and the mould is returned to the vatman. The felts
are woollen cloths of close texture, resembling that of
machine blankets, and are larger than the paper placed
upon them.

Upon each sheet of paper a third worker places
a felt, and the papermaking proceeds. When the pile
of felts and paper is sufficiently high, it is transferred
to a hydraulic press, and considerable pressure is
applied in order to remove as much water as possible
by squeezing, and, more important, to couch or press
the fibres together and to close the sheets. The pile
is removed, the felts taken out, the pile of paper given
further pressing, and for some papers the paper is
turned, rebuilt, and pressed again, to improve the close-
ness of the sheets. The paper is then taken to the
drying loft, hung on ropes of cow hair, which material
possesses the virtue of making no marks or stains
upon the tender paper. Loft-drying is carried on
at an even temperature, in order to permit of even
shrinkage of the sheets. At this stage the paper,
which is unsized, is known as waterleaf, and unless
it is to be used in the unsized state, requires further
treatment, as described in the next chapter, before
being ready for use.

Mould-made papers are made by machine as far as
making the sheets is concerned, other operations being
carried out as for hand-made papers. The moulding or
forming of the sheet is carried out in different ways on
different machines, but the construction of the machines
being kept secret by their users, it is not possible to
give a description here.


THE Fourdrinier machine bears the same relation to the
hand mould that the rotary press does to the hand
press. Instead of making paper sheet by sheet, it
makes it in a continuous web, on an endless band of
woven wire. The machine in a much simpler form was
invented by a Frenchman, Nicholas Robert, the first
machine being made in 1799, and so rapidly did the
machine find favour that in fifty years over 150 paper-
making machines were at work.

Papermaking by hand involves the processes of
transferring a certain and regular quantity of pulp from
the vat to the mould, shaking the mould to felt the
fibres and to remove the water, couching the paper and
drying the waterleaf. Machine-made paper follows the
same processes exactly, everything being done by the
one machine, including sizing. Viewing the paper-
making machine, it appears to be a collection of
machines carrying out the separate functions in proper
sequence. The different parts of the machine can be
controlled and driven at different speeds for special
reasons. Thus a definite and regular quantity of pulp
is taken, shaken, the water removed, the soft paper
couched, pressed, dried, and a finish given to the surface
of the paper, all in the compass of the one machine.

The pulp as left at the end of Chapter II. was
merely beaten fibre, and if an unsized paper were



FIG. 5. Diagram showing elevation of Papermaking Machine. Shown in Sections.

Total length of machine 144 feet.
(Built by Bertrams Limited, Sciennes, Edinburgh.)


required the pulp would be let down to the stuff-chest ;
but usually other things are added before the pulp is
ready for the machine. Filling or loading, colouring
matter and sizing material, are mixed with the pulp,
thoroughly incorporated, and then the engine is emptied.

Paper can be made without filling or loading ; in
fact all-rag papers seldom contain mineral matter, and
many excellent papers are made from other fibres with-
out loading. The purposes of loading are to fill the
spaces between the fibres, to give opacity to papers,
such as those made of sulphite wood pulp, which would
otherwise be very transparent, and to enable the paper
to take a higher finish than would be possible in a
paper without loading : a smoother and more absorb-
ent, even if a little weaker, sheet, resulting. In a
blotting paper mineral matter is an adulteration ; in
writing papers 5 per cent, is sufficient for improve-
ment of surface ; in printings I o to 1 6 per cent, is
as much as is permissible. In an imitation art paper
as much as 25 per cent, may be added, and yet a
serviceable paper result ; but of course the tenderness
of imitation art paper will be present.

China clay is the usual material used for filling or
loading. It is mixed with water, and strained before
filling into the beating engine, and the colour is added,
either to produce a coloured paper, or to correct the
tendency to greyness in the finished paper. In the
latter case, a little blue and perhaps a little red is
added, while in the former case the colour may be
added, or formed in situ by the mixture of different
chemicals in the beating engine. Dry colours, whether
pigment as ultramarine or aniline colours, are mixed
with water (dry patches being difficult to deal with in
the pulp), and then added to the pulp in the engine ;
when the colours are thoroughly mixed, alum is put


in. Alum serves to mordant or fix the colour, and also
serves to precipitate the resin size which is next added.

There are various prepared sizes on the market to
take the place of the size prepared by the papermaker
from resin and a solution of soda. The resin is melted
and added to the soda solution, and boiled until the
solution is complete. The size solution is added to the
pulp in the beating engine, and thus we get a clue to
the meaning of E.S., or engine-sized paper.

The pulp now consists of innumerable fibres, to
which and in which are fixed small particles of china
clay, colouring matter, and resin. In many writing
papers a small amount of starch paste is added, and
that also adheres to the tiny fibres. The engine is
emptied by gravity into the stuff- chest, where the
revolving arms keep the fibres in the mixture from
precipitation. Then there is a short journey to the
machine, during which the pulp undergoes great tribu-
lation, first being diluted with a large quantity of water,
then passing over sand traps which intercept grit,
metallic fragments, and such matter that is heavier than
the pulp and so tends to sink, and then through strainers,
which retain foreign matter, unbeaten particles, and
knots of fibre. The flow of pulp is governed by a
system of valves, which can be quickly manipulated to
alter the substance of the resulting paper.

The wet end of the machine consists of an endless
band of woven wire, some 40 to 80 meshes to the inch,
from 48 to 205 inches wide, and a total length of
40 feet or more. The length of wire in use at one time
as a paper mould is less than half its total length. This
woven wire corresponds to the mould of the vatman in
hand-making. Deckle straps, the substitutes for the
vatman's deckle, are thick endless rubber bands, square
in section, which rest on the wire cloth, and, following



the travel of the wire, return over pulleys, serving the
same purpose as the deckle, namely, to confine the pulp
to the wire surface. The wire cloth is supported by a
number of rollers tube rolls which keep the wire from
oscillating, and assist the passage of the water through
the wire. The end of the wire nearest the stuff-chest
is kept shaking backwards and forwards to cause the

FIG. 6. Front View rom Strainers ot 94-inch Papermaking

(Built by Bertrams Limited, Sciennes, Edinburgh.)

fibres to felt before the water has passed through the
wire. The pulp passes from the strainers under a slice,
which distributes the pulp evenly, over a rubber apron,
on to the machine wire, and near the end of the wire
will be seen a cylinder of wire above, and square boxes
below the wire.


The cylinder is the dandy roll, which closes the
surface of the paper with slight pressure, and if a water-
mark is required the soft pulp is impressed with the
design upon the surface of the roll. If the paper is to
be " laid " the cylinder will be covered with laid wires,
with tying wires at regular intervals, but a wove paper
has a woven dandy roll which leaves no mark beyond
any watermark that may be on its surface. A dandy
roll on which the tying wires run the length of the roll
instead of round the circumference is known as a spiral
laid dandy roll.

The boxes beneath the wire are suction boxes,
open mouth of pumps which suck the remaining water
from the paper. The wet end is well named, as for
every ton of paper nearly 20,000 gallons of water are
used for the dilution of the pulp, so that it may flow
evenly and regularly. This water passes through the
wire, most of it falling into the save-all and is used again
for diluting the pulp.

Passing under the dandy roll and over the last
suction box, the wire carries the web of paper through
the couch rolls, where the paper is couched or pressed
by a felt-covered roll for the same reason as hand-
made papers are couched : to consolidate the paper.
The wire returns to perform its operations continuously,
and the limp paper is carried forward to the press
rolls, where it is further pressed by polished rollers,
first one side, then the other, to remove the wire
and felt marks. Then the paper goes forward to the
drying cylinders massive rolls heated by interior
steam ; but the heat is so regulated that it is gradually
increased, and the speed at which the web of paper
travels is arranged so that no undue tension is placed
upon the paper, or thinning might result, or the web be
broken, and delay caused. The drying section of the

FIG. 7. End of Wove Dandy Roll.

FIG. 8. End of Laid Dandy Roll.

FIG. 9. End of Spiral Laid Dandy Roll.


machine is a very quiet place compared with the wet

At the end of the machine are stacks of rolls
through which the paper is led if it is to receive what
is known as " machine finish." If, however, the paper
is to be super-calendered, it is led past one or more of
the stacks of rolls, and as it is reeled off a fine spray
of water is projected upon the paper. There are
various means of producing a misty cloud, but the
object is the same in every case, to restore some of
the moisture which has been driven off, and to prepare
the paper to receive the finish at the super-calenders.
If the paper were finished bone dry it would not be
possible to impart the required surface by super-
calendering, and, too, the paper would at the first
opportunity absorb moisture from the atmosphere, and
various troubles would arise. The paper, now reeled,
is ready for the finishing department, to which the next
chapter is devoted.

Papermaking on the Yankee or single cylinder
machine is conducted in the same manner as on the
ordinary or Fourdrinier machine as far as the wet end
is concerned, but the series of drying cylinders is
replaced by a single cylinder of large diameter, as much
as i o feet in some instances : the paper passing round
this heated cylinder is dried, and glazed on one side,
hence the term M.G., or machine-glazed paper.

Mill numbers survive from the time when all mills
were registered, and when paper was a dutiable article.
The duty was repealed in 1861, but the mill numbers
remain, and are additional to watermarks in distinguish-
ing between papers of the various makers.

Watermarks have been used from very early times
to serve as marks of distinction. The watermark used
by John Tate of Stevenage in 1494 was an eight-




r ~o





petalled flower. The cap and bells, post horn, crown,
fleur-de-lis, and tankard have been associated with
foolscap, post, crown, royal, and pott respectively, but
the connection between size and watermark is not very
close. At present foolscap papers frequently bear the
figure of Britannia, and royal papers a shield, with bend
sinister, surmounted by the fleur-de-lis. The register
of watermarks consists of a large number of names
which are intended to make the papers bearing them
proprietary articles, and as the quality of the paper is
maintained by the papermaker, there is almost an
indirect virtue in watermarks. Special watermarks are
sometimes designed for special editions or for paper for
special purposes, the dandy roll being made in length
and diameter to suit the size of the paper to be made.
Watermarks on hand moulds are placed in position on
the moulds, and there is no difficulty in cutting the
paper to obtain register of the marks, as in the case
of machine-made papers.


PAPERS which have reached the stage described in
Chapters III. and IV. still have much to be done to
them before the consumer, stationer, or printer can
receive them. Finishing varies with different papers.
Hand-made paper requires sizing, drying, glazing, sort-
ing, counting (sometimes cutting), and packing before
it is ready for despatch. If the machine-made paper
is for writing, it may be gelatine sized, followed by
drying, re-reeling, glazing, cutting into sheets, sorting,
counting, and packing into reams. Printing papers
are finished with " machine " or with super-calender or
water finish, and other papers with friction-glazed or
flint-glazed surfaces, the other operations following as
for other papers after glazing.

Tub sizing always means animal sizing. Some mills
still prepare their gelatine from hide cuttings, parchment
cuttings, and other materials which yield gelatine, but
the tendency is to eliminate this process and to buy the
gelatine in sheet form ready for use without any process
other than reduction to a solution of such strength as
is necessary. The tub or vat of size is prepared and
kept at an even temperature, the paper is dipped or
allowed to stand in the size, or there are machines
which carry the paper slowly through the trough of
gelatine. The size must permeate the paper in order
to make the sizing effective. On emerging, the paper



is squeezed to remove the excess of size, and the sheets
are separated to prevent the paper from becoming a
solid block.

The second visit to the drying loft prepares the
paper for the last stages of manufacture. The drying
is conducted at a moderately low temperature (for
papermakers), not exceeding 80 Fahr., and when
dry the paper has its bulk reduced and its surface
improved by plate rolling, unless it is a drawing paper
with a " not," that is, a rough surface. Plate rolling
necessitates building a pile of paper, alternated with
zinc plates a little larger than the paper, unbuilding
and building of piles proceeding simultaneously as in
the case of taking out set-off sheets and interleaving
newly printed work. One girl takes the glazed paper,
a second removes the plates, a third feeds the unglazed
paper to the plates. When the pile is high enough it
is lifted to the pressing rolls by a man who feeds it
between the rollers, where great pressure is given, and
the pile automatically returns to the front of the
machine, and it is turned and placed for pressing the
other way of the sheet. From two to a dozen pressings
will be given according to the degree of finish required,
and also to the hardness of the material.

Sorting, counting, and packing will complete the
cycle of operations included in finishing, unless cutting
to size is also necessary. Girls stand at long benches
lighted with large windows, and have piles of paper
before them for sorting into three classes good,
middling, bad according to the degree or absence of
defects. The middling paper showing slight defects
is known as " retree," the reams are marked x x , and
the paper is sold at 10 per cent, reduction on the price
for good paper. Bad paper, showing glaring defects, is
called " broke," the reams are marked x x x , and it is


either sold at a further reduction or is returned to be
repulped. If the order is for specially watermarked
paper, or is for all " insides " or good paper, the " re-
tree " and " broke " will both return for re-making.

Machine-made writing papers which are to be
sized with gelatine are usually first sized with resin, so
do not come forward as waterleaf. The sizing room is
long, high, comparatively narrow, containing a small
sizing machine and numerous drying cylinders. The
reel of paper is mounted on brackets in front of the
sizing trough, the web passes between metal rollers, be-
neath the surface of the warm size, out and between
squeezing rolls which remove the excess of gelatine,
and then forward for drying. Up to the roof, and down
to the floor, over skeleton drums, the web of paper travels
until it is thoroughly dried, in a temperature equal
to that of the drying lofts. At the end of the room
the paper is reeled again, and when in a fit state goes
either to the super-calenders, or, if the paper is to
be plate-rolled, it is cut and the surface imparted as
described for hand-made papers.

Papers which are merely to have " machine-finish,"
that is, the surface imparted by the calenders of the
paper machine, receive no further treatment before
being cut into sheets. Those papers which are to
be super-calendered (S.C.) pass through a large super-
calendering machine, consisting of a number of chilled
iron rolls and rolls of compressed cotton or paper
alternately. The weight of the rolls is enormous,
and although extra pressure can be applied, it is not
often necessary. A very high degree of finish can
be given by means of the super-calenders, and the
majority of papers with a glazed finish have passed
through this machine.

Papers which are to receive a water finish are


given a film of water on the surface just before the
web passes between the rolls of the super-calender, and



FIG. ii. Web Glazing Calender or Super-Calender.
(Built by Bertrams Limited, Sciennes, Edinburgh.)

as a result the mineral constituent of the paper is
brought to the surface, and a very level finish, with
a high degree of polish, is imparted to the paper.


Friction glazing produces a higher polish than
the processes already described. The machine is
simple in construction, consisting of a pile of three
rolls, one of cotton between two of steel. The paper
passes between two only, and the top roll, being driven
at a higher speed than the others, burnishes the side of
the paper against which it is driven in a much more
effective manner than the super-calenders.

Flint-glazed papers are actually burnished by the
surface of a stone passing rapidly backwards and
forwards on the surface of the paper as it emerges
from the rolls, giving a hard brilliant polish. The same
degree of finish is imparted to some papers by the use
of a number of brushes oscillating rapidly upon the
paper as it travels over a large cylinder.

Cutting the reels into smaller widths and then into
single sheets is the function of a number of ingenious
machines. If a watermarked paper is to be cut to
register, a single reel is mounted at the cutting machine,
and the web is advanced the necessary distance and
the division into sheets takes place by a knife. A boy
watches the travel of the paper, and when the water-
mark travels beyond or short of a pointer, a turn of
a screw brings the next sheet into register. Single
sheet cutters are used for other papers, the reel is
mounted, run forward between slitting knives, and a
swinging knife divides the paper into sheets. Another
make of machine will take from one to seven reels, and
the paper passing between the slitters is cut into sheets
by a revolving cutter, which makes a clean cut the
whole width of the web, and the sheets are dropped on

2 4 5 6 7 8 9 10 11 12

Online LibraryEdward A DawePaper and its uses : a treatise for printers, stationers and others → online text (page 2 of 12)