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Edward A Dawe.

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

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If the paper were heavily rolled it would reduce its
usefulness as an absorbent paper. Featherweight



DURABILITY OF PAPER 65

papers are made entirely of esparto, finished to produce
as bulky a paper as possible, consequently the fibres
are not well rolled together, and the books printed on
such paper are anything but durable. Imitation art
papers give a mineral residue of 25 to 35 per cent,
on ashing, and have very little strength, owing to
the large proportion of china clay present.

Art papers do not fold or stitch well, as the mineral
coating, although firmly fixed to the paper, behaves as
a non-fibrous material might be expected to do, break-
ing down, and the paper beneath tends to give way
too. If kept in a damp place art papers absorb
moisture at the edges, and in the presence of a large
amount of moisture the sheets will stick together.
Rag art papers are procurable (the body being a rag
paper), and possibly it will be found that such papers,
kept from air and moisture, will be very durable.

Papers containing a large proportion of mechanical
wood, whether coated or otherwise, are certain to
deteriorate rapidly. A newspaper exposed to sunlight
for a day or two becomes discoloured and brittle, the
same result following in a longer time if exposed to
light and air without the sun. For this reason papers
containing mechanical wood should never be employed
for work which is to last. Cheap reprints of standard
works are sometimes printed on such paper, but it is a
very doubtful economy on the part of the publisher.



CHAPTER XIII
DEFECTS AND REMEDIES

MANY users of paper look upon that material as being
perfectly inert and stable, always of the same quality,
and any defect which may arise remediable only by
changing the paper. Unfortunately, the printer who
uses the paper for letterpress, lithographic, or ruling
purposes, finds that paper is not unchangeable, and
when work has to be registered upon the paper diffi-
culties often arise, and exchange is not always possible.

The principal difficulties arise from stretching,
cockling, creasing, from the surface lifting or picking,
from the paper being out of square, from electricity
contained in the paper, and from loose particles coming
away from the paper in the form of fluff. In addition
there are difficulties in getting colour to dry upon
certain papers, and in obtaining a solid impression or
continuous line from printed or ruled matter.

Reference to the chapter on machine-made papers
will serve to give the clue to some of the difficulties,
and may suggest the remedy. The pulp, diluted with
a large volume of water, consists of innumerable fibres,
their length being at least 100 times their diameter,
and as is the case of all water-borne bodies travelling
in a fast stream, they take up the position in which
their length is parallel to the direction of flow. The
side shake of the wire alters the position of some of
the fibres, and although the alteration is permanent,

66



DEFECTS AND REMEDIES 67

the majority of fibres remain in a position parallel to the
machine direction of the web of paper. Most machine-
made papers are dried on the heated cylinders of the
paper machine, the diameters of the cylinders being
arranged to allow for the consequent contraction of the
web, but the fibres are not given the opportunity to
adjust themselves as in the case of air-dried papers.

When it is remembered that the papermaking
fibres may expand in diameter to the extent of 20 per
cent., but only one per cent, in length, it will be seen
that the expansion will show itself chiefly in one
direction, for the majority of fibres lie side by side.
Fortunately the full expansion does not take place.
Paper which is properly matured contains water
equal to 7 per cent, of its weight. Without this
moisture, paper would be brittle, and when this amount
is exceeded the paper expands. But paper, as it
leaves the calender rolls of the paper machine, contains
less than 7 per cent, of water. It is essential that all
the water should be dried out of the paper, and the
paper is sometimes reeled almost bone-dry, but if the
paper is to be super-calendered it is damped before
reeling, and left until the paper mellows before calender-
ing. Many papers are cut and packed without much
opportunity for maturing, that is, as regards paper,
attaining a degree of stability which should be main-
tained during its manipulation by the printer, and, it is
hoped, during the remainder of its career.

All papers have some spaces between the fibres,
sometimes partly filled with sizing and loading, but
always containing some air space, the amount depend-
ing upon the density of the paper. Heavy or dense
papers and light or bulky papers are the extremes,
30 to 70 per cent, of air space being examples of
the two ends of the scale. The fibres, when expanding,



68 PAPER AND ITS USES

fill some of the air spaces between the fibres, and
the expansion can never extend to the 20 per cent,
mentioned. Experiments carried out on a litho. paper,
36 Ib. royal, showed the maximum expansion from
absorption of moisture to be 2 J per cent, but papers do
not expand as much as this in working, or register
work would be extremely difficult.

Expansion, or stretching as it is usually termed,
is caused by absorption of moisture by the finished
paper from the atmosphere. The atmosphere always
contains some moisture, the amount varying not only
from day to day, but from hour to hour. When there
is an excess of moisture in the air, as on wet days
or when fogs occur, paper will readily absorb the
extra moisture, and the absorption will be accompanied
by expansion of the sheet, principally across the web,
or as it is generally termed, in the cross direction.
This propensity of paper really points to the remedy.
Paper should be matured and kept in that state, or
to put it in other words, it should contain an amount of
moisture which is neither increased nor diminished.

Few printers treat the machine-room, letterpress or
lithographic, or the ruling-room as places where scientific
conditions should be maintained. The use of the wet
and dry bulb thermometers in other factories is for a
definite purpose, to indicate the state of the atmosphere,
and to guide in regulation of temperature and humidity,
in order that the manufacturing processes may be carried
out under scientific conditions. But the machine-room
of the printer, closed for more than half its time, heated
perhaps by hot water or steam pipes, sometimes hot,
sometimes cold, in wet weather damp, in summer
alternately very dry and damp, what wonder if paper
expands, contracts, and causes trouble at machine.

The establishments where scientific conditions are



DEFECTS AND REMEDIES



6 9



observed reap the benefit in increased output, because
less work is spoiled by bad register, and less time
is spent in getting work to register. Even with the
regulation of atmosphere suggested by the use of the
dry and wet bulb thermometers or hygrometer, the
paper must be matured in the machine-room, that is, the
paper must be exposed in order to allow it to absorb
moisture if too dry, and to part with moisture if too
damp, so that the paper may be as stable as possible
while the condition of the machine-room remains
constant It is important that the amount of atmos-
pheric moisture should remain constant, and printers'




FIG. 12. Ball Frame for Hanging Paper.

engineers will advise on the means of attaining this
end.

Various methods may be adopted for suspending
paper. In some cases the paper is hung over lines,
about a quire at a time, exposed to the atmosphere
and dust of the machine-room. Hanging frame:; are
supplied by vendors of printers' supplies, in which
the paper is clipped by a ball or swinging lever,
and about a quire is held in each of the clips, a
perpendicular position minimising the danger of dirt.
By use of these frames a large quantity of paper can
be treated in a comparatively small space. The
" Swift " machine is another method of maturing



70



PAPER AND ITS USES



paper. The claim made for the machine is that it
matures large quantities of paper in a short time.




I

Pi



The machine consists of two sets of fans, enclosed by
iron framing, driven by motor attached or by existing



DEFECTS AND REMEDIES /I

motive power, some four to six reams of paper being
suspended in ball clip frames in the space between
the two sets of fans. The air of the machine-room
is circulated by the fans rapidly through the paper,
and maturing takes place in two or three hours.

All paper, after it has been matured, must be
stacked, a board and a heavy weight placed on the
top of the stack, and the edges protected from .getting
dirty.

Stretching takes place when paper is subjected to
tension or rolling. All cylinder printing machines
exert these strains, from the pull of the cylinder and
from the printing surface. Difficulty in register will
be experienced when a paper stretches much under
tension, but it is not so great a trouble as the
expansion already referred to. All papers are elastic,
and if stretched just within the bounds of the breaking
strain of the paper, will show some elongation, per-
manent or temporary. If the paper returns to its
original length there is no permanent stretch, but that
is seldom found in practice. The greater expansion
of paper is in the cross direction, and the direction of
greater stretch of the sheet coincides with that of the
larger expansion.

Careful tests of good litho. papers on the Leunig
Paper Tester show them to have a mean temporary
stretch of 2\ per cent, in the machine direction, with
a stretch that is permanent of '68 per cent. The
figures for the cross direction of the paper are 4 per
cent, and I -i- per cent, respectively. It is the per-
manent stretch that may cause inconvenience, but the
figures quoted must not be taken as an indication
of what takes place when printing. A properly ad-
justed machine does not exert the tension that would
be necessary to obtain the percentage of elongation



72 PAPER AND ITS USES

shown above. The fact that lithographers prefer papers
cut with the cross direction coincident with the nar-
rower dimension of the sheet is sufficient proof that it is
not the machine tension that is dreaded in register work.

Writing and most printing papers, which may or
may not be printed in more than one colour, are
frequently cut two ways of the webs, that is, a 30 by
40 inch paper, if cut from a web of 70 inches net
width, is cut without waste by cutting sheets 30 inches
wide from one part and 4O-inch sheets from the
remainder of the reel. All papers on which register
work is to be printed must be cut with the same
machine direction. In ordering paper which is not
generally used for work in several printings, the printer
should be careful to point out the purpose for which it
is intended, and ask that the instruction shall, if
necessary, be passed on to the papermaker.

Cockling in paper is caused by the paper being
drier or damper than the atmosphere, and shows that
there is unequal expansion of the sheets, and exposure
as detailed above should be tried as a remedy. Card-
boards which are cockled may or may not improve
upon exposure to the atmosphere. The thicker the
cardboard the less likely it is to alter its shape.
Usually the fault will have arisen through severe
drying under tension, stretching the boards, and
drying while unequally stretched. The cockling and
wavy edges of boards are frequently found to be
permanent faults.

Wavy edges to paper, if at the feed edge, will
frequently cause bad creasing, from which damage to
the printing surface may result. Creasing from defects
of the machine, make-ready, or printing surface must
not be visited upon the papermaker. If the paper will
not respond to exposure to air, feeding the narrow way



DEFECTS AND REMEDIES 73

of the sheet may overcome the difficulty, or, if the size
of the machine permits it, cutting the paper in half and
rearranging the forme or other printing surface and
putting on an extra feeder.

Art and other coated papers which have the coating
fixed to the paper with glue in addition to the liability
to wavy edges, may be troublesome by reason of the
surface lifting or picking. The latter fault is caused
by the coating being insecurely fastened to the body
paper, the trouble being temporary or permanent.
Storing the paper in a damp place will weaken the
adhesive properties of the glue, and the coating will
not stand the pull exerted by the printing surface, but
will come away in places. The paper may be improved
by suspending it to dry off the excess of moisture, but
if heated air is used, the temperature should not exceed
90 Fahr. Newly coated papers may cause trouble,
owing to the adhesive not being quite hard, and keeping
in stock for a fair length of time, a month or two, may
result in an entirely satisfactory issue. But if the
papers must be used, maturing as already described,
with a careful use of heat, will usually remove the
trouble altogether. Slight modification of the ink may
be necessary, and should be tried before condemning
the paper altogether.

; It will be found occasionally that the coating is not
properly fixed to the paper, owing to insufficient glue,
or a soft-sized body paper being used. Damp the
thumb and press on the coated paper, lifting it a few
seconds after. If a large part or the whole of the
coating comes away the coating is at fault. Crumple
a piece of the paper, treating it rather severely, and
note the amount of coating which has left the paper
when flattened out again. A large amount of dust
indicates bad coating. Comparative tests should be



74 PAPER AND ITS USES

carried out, a sample known to be satisfactory being
tried by the side of the suspected sample.

Fortunately papermakers do not often offend by
sending supplies which are out of the square. It does,
however, sometimes occur that one edge of the paper
is not quite true ; folding a sheet in half, with the short
edges coincident, will show the extent of deviation from
squareness. For ordinary purposes it may not be
material if one edge of the paper is one-eighth of an inch
out, but if the sheet has to be backed up, care must be
taken to feed the longer side into the grippers and to
place the side lay, when backing up, at the opposite
side exactly at the same point as when first fed. This,
of course, is the printer's rule, and in such cases it must
be rigidly observed. When paper is fed to the narrow
edge, as when two sheets of demy are laid on a double
demy machine, the square edge must be the lay edge,
or the register of the backing forme will be impossible.
For colour work the only safe rule is to trim the two
lay edges of all the paper, and, if necessary, to use a
larger paper to allow for the trim.

Electricity in paper causes delay in feeding, the
sheets sticking together, necessitating an undue use of
the cylinder stop. As the paper is reeled at the end
of the papermaking machine, electric sparks are
frequently to be observed, owing to the electricity
generated by friction of the dry paper. A large
quantity of the electricity is extracted, but some thin
papers with high surface will retain a fair amount, and
sheets cling together. Paper which has been exposed
for maturing will not give this trouble, and thick
papers, even if electrified, do not usually call for special
treatment. Elaborate methods have been suggested
for discharging the electricity in the paper, but it is a
difficult matter, and the most satisfactory plan is to set



DEFECTS AND REMEDIES 75

aside the reams which are troublesome, and in time the
electricity will disperse. The use of automatic feeding
mechanism is sometimes quoted as a cure for this trouble.

Papers which are loose in texture are usually soft-
sized, and thus, having comparatively little size to hold
the fibres together, will give off fluff or dust, consisting
of small fibres, as soon as the paper is subjected to
friction, even of the lightest description. Such paper
in its passage through the printing machine gradually
deposits its fibrous dust upon the printing surface, the
rollers take it from there to the ink distributing surface,
and the whole of the inking and printing becomes foul.
Such papers are extremely difficult for lithographic
printing, and the letterpress printer consumes most of
such papers. Soft papers with the mill cut are slightly
rough and give off dust, and trimming a clean edge
reduces the liability to fluff, but cleaning up at machine
(forme, rollers, and ink slab or drum) will be necessary
more frequently than is usual. When the machine
is stopped for washing up, all parts of the machine
carriage which can be reached should be wiped free
from dust, as the accumulation will gradually find its
way to the rollers when the machine is in motion.

The proper ink for the paper will prove the solution
for difficulties in printing on hard papers, and also on
very soft papers. It is outside the scope of this work
to deal with printing inks, but in regard to coated
papers it will be found that all such papers do not
behave alike. Some take the ink readily and retain
the fullness of colour, while others soak up the varnish
and leave the dry colour on the surface. The latter
fault is owing to the absorbency of the body paper,
and ink must be treated so that the absorbency of the
paper is satisfied, and yet the colour and medium
remain more on the surface of the paper.



76 PAPER AND ITS USES

Ruling on papers with hard surface is rendered less
difficult by the use of a small amount of gall in the
ink. For hand-made papers the ink always requires
such manipulation, while for other tub-sized papers a
little gum arabic in addition to the gall will render
even ruling more easily attainable. In ruling engine-
sized papers a small amount of gum arabic and
carbonate of soda (ordinary washing soda) will make
the colours lie better. While all work can be done on
the pen machine, papers with soft surfaces, blottings,
duplicating, metallic, and coated papers generally, will
give the disc machine opportunity to prove its superiority
for this class of work. Cockled papers and very thin
papers can be dealt with successfully at the ruling
machine by a little manipulation of the pens and feed.

Although rolling, hot or cold, may be effectively
used for giving finish to the printed work, the paper is
subjected to such great pressure that it is liable to
stretch. As pointed out earlier in the chapter,
stretching of paper is not equal in both directions of
the sheet, and it is advisable, in order to preserve the
strength of the paper, to roll in the same direction as
the paper was made and rolled in the papermaking
machine. Discover the machine direction by the
method described on page 86, and feed the paper to
the rolling machine in the same way as it left the
papermaking machine.

Tub-sized papers may contain or develop a fault
which will not occur in engine-sized papers, that of
unpleasant smell. A preservative of some kind is
frequently added to the sizing solution, but if the
gelatine has commenced to decompose the smell will
be at least unpleasant. Coated papers contain glue
in the coating mixture, and are liable to the same fault.
Printers should be careful when buying job lots of tub-



DEFECTS AND REMEDIES 77

sized or coated papers that the cause of the inclusion
in the job list is not smell, for a customer cannot be
expected to accept a big parcel of printed matter for
circulation which is offensive to one of the finer senses,
and therefore not likely to prove persuasive to the
recipients.

Deterioration of paper has been dealt with already,
but there are faults unwittingly developed in some
paper which can be avoided by the application of a
little forethought. The colouring matters of papers
are affected by various things. Some blue colours are
discharged (bleached) when acid in any form comes in
contact with them, others behave similarly when alkali
is encountered. Some buff papers are altered in shade
or even in colour by the same agents, and other colours
are affected by some but not by all acids. It is not
proposed to examine the composition of the colours
used by the papermaker, but to point to instances
where care is required. When the printer or manu-
facturing stationer is covering strawboards, boxboards,
or millboards with coloured papers, paste or glue may
be employed as adhesive, and these are always liable
to become acid. To avoid change of colour the use of
freshly prepared paste or glue should be adopted.
Strawboards frequently contain a certain amount of
free alkali, and the colours of papers or cloth mounted
upon them may be affected. It may be necessary to
change the paper to one which is unaffected by the
strawboard, and if this is not feasible, a change of
board may be necessary. It is not practicable to
neutralise the alkali, as fresh trouble may be caused,
and an unsatisfactory result be obtained. Before
starting on a big job, tests should be made with the
actual materials so that no serious loss by spoilage or
stoppage may occur.



78 PAPER AND ITS USES

All knives, whether circular or straight, must be
kept keenly sharpened in order to produce clean edges.
Soft cards and papers give more trouble than moderately
hard stock when cutting in a guillotine. Some
materials should be cut by the rotary cutter when
exact measurements are essential, for although it may
take longer, for index cards all supplies must be
trimmed exactly to the same dimensions, and the very
hard index boards are liable to be cut irregularly by
the guillotine.

When sheets are ruled or printed, and are after-
wards to be bound, the printed or ruled horizontal lines
should coincide with the machine direction, or, as it is
sometimes expressed, should run with the grain of the
paper. The stitching and the binding which secure
the leaves will then be fully operative, whereas if the
paper is held with the back of the book parallel to the
machine direction, the leaves are more liable to break
away from the binding.



CHAPTER XIV
THE RIGHT PAPER

SELECTION of paper to suit a particular job calls for
experience in handling both the finished work and the
plain paper. Judging papers as being equal to patterns
or samples, and forming an opinion of comparative
values, are also to be gained only by long experience.
A few guiding principles, without making a royal road,
may render the journey somewhat less laborious.

The varieties of papers already described writings,
printings, coated, and other papers are accompanied
by indications of their general purposes, and the
inexperienced should be kept from making bad
blunders. Common sense will prevent the mistake
which is still perpetrated of printing a half-tone block
on a laid paper, or a paper with a heavy watermark.
The laid lines and the watermark show up through the
half-tone impression and spoil the picture. Half-tone
work demands a perfectly smooth paper, coated or a
good super-calendered paper being the best.

Very few papers are identical in finish on both
sides of the sheet, and it should be the first thing
taught to the apprentice that all one-sided work should
be printed on the right side of the paper. A matter
which is seldom referred to is the position of the water-
mark. When cutting paper, the paper should not be
turned so that in a ream one-half of the paper has the
watermark reading correctly, while on the other half it

79



80 PAPER AND ITS USES

is upside down. If the paper is ruled or printed in the
sheet, the pens and type or transfers should be arranged
to keep the watermark the right way. In the case of
folded and stitched work this is not possible without
special watermarking, but for all stationery these pre-
cautions should be taken.

When judging paper or cards it must always be
remembered that a sheet may compare very badly with
a small piece, therefore when making comparisons the
sizes of the samples of paper or card should be cut to
the same size. Only by adopting this practice can
weight, colour, and texture be judged accurately.

Choosing a paper suitable for the work in hand is
simplified when one knows what is used for similar
work. For ledgers, account books, and all work of
that character, a strong, tough, well-finished paper, cap-
able of taking writing ink easily, and able to bear ink
after erasure should be used. An opaque all-rag, azure
laid, tub-sized paper, of moderate weight, 34 Ib. in


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Online LibraryEdward A DawePaper and its uses : a treatise for printers, stationers and others → online text (page 5 of 12)