CONCERNING PAPER
Three kinds of paper are used mainly in lithography. They are:--
(_a_) the transparent, oiled or varnished paper;
(_b_) underlay or waste paper; and
(_c_) the printing-paper.
I
TRANSPARENT PAPER, AND THE TRANSFER OF OUTLINES TO THE STONE
Oiled paper is used for tracing a drawing accurately and then
transferring it to the stone either by transferring or by re-tracing it
on the stone. It must have the following properties:--
(1) It must not smut the original drawing on which it is laid.
Consequently it must be absolutely dry.
(2) It must be very transparent, like glass, so that the underlying
drawing or painting can be seen perfectly.
(3) The ink or lead crayon used for copying must lie on it easily and
plainly.
It is at its best if it is easy to work on it with a fine brush, using
Chinese ink, or, (if the drawing is to be transferred directly to the
stone), with the soft chemical ink described under the caption "Transfer
Ink." Generally this can be done without further preparation in the case
of most papers made transparent by oiling. Varnished paper, however,
which is far more transparent, generally must be well washed with milk
and dried again beforehand, that it may take the ink well and permit
work with the finest strokes.
(4) Finally, a good tracing-paper must be very fine, pliable, tender and
yet not in the least brittle. There is some very transparent varnished
paper, but it breaks at the first attempt to bend it, so that it is hard
to trace the drawing afterward on stone with the tracing-needle,
because nearly every stroke tears the paper and the lines and outlines
become coarse.
Very good transparent paper may be made as follows:--
Take the finest writing or vellum paper and soak it with nut or poppy
oil, mixed with a little sugar of lead to make it dry more readily. When
well soaked with oil, dry it a bit between waste paper and hang it up.
Usually it is available in a few days. This paper is cheaper than the
paper sold by stationers under the names of straw paper, etc., and about
equally transparent. Still more transparent will it be if instead of the
oil a varnish cooked from the oils is used. In this also the sugar of
lead is an excellent drier. To make the varnish easier to manipulate and
more readily penetrative for the paper, it may be thinned down with oil
of turpentine. If it is desired to manufacture a greater quantity of
this paper, one sheet is laid on another and painted with varnish. Then
the whole mass is left for some time covered with a stone plate or a
board, that the varnish may soak properly and evenly into all the
sheets. Afterward the sheets are hung up singly to dry. The more varnish
they have, the more transparent will they be; but too much is not good.
Care must be taken that no drops of varnish adhere. It is best to brush
the varnish evenly over each sheet before hanging it up.
Silk paper, such as is used in copper-printing to lay between
impressions to prevent off-set, is still better for varnishing because
it is finer. Only it must be very even and have no holes. The very
greatest fineness of paper is desirable, for the reason that then the
strokes made by the needle on the stone are fine and not coarse.
Instead of varnish made by boiling down nut or poppy oil, one can use
Venetian turpentine, which merely has been thinned down with one half as
much oil of turpentine. Such paper generally is dry enough after
twenty-four hours. Too large a quantity must not be made at one time,
because it becomes tough and brittle after a while.
Even with the most transparent paper it occurs that certain delicate
drawings, and especially color pictures, will not show through
sufficiently. Then the drawing must be fastened to a window pane to
obtain added illumination. This manner of work is very uncomfortable,
however, and the arms hurt one soon, so that it is necessary to stop. It
is better to have a tracing-board made with a strong, clear pane of
glass in the centre. Under it is a mirror so adjusted that it reflects
light upward through the drawing.
It is understood, of course, that in tracing only the outlines are
copied and not every stroke of shading, etc. Although the final work is
greatly facilitated by the observation of the utmost care in tracing,
the tracing of every little detail will merely make the work involved
and perplexing. Practice must show the proper degree of exactness. A
very good and skillful artist often needs only a few main outlines, to
reproduce the original picture with the greatest accuracy.
Once the drawing has been traced sufficiently, the transfer paper must
be coated very lightly and evenly with red chalk. Then it is fastened to
the stone with wax and all the lines are traced under moderate pressure
with a well-polished needle whose point is not sharp but rounded. Where
the needle presses the tracing-paper, the color that is on the other
side will take hold of the stone and thus transfer the drawing to it. If
the needle is too sharp, it will injure the paper, and often the stone
and the etching surface. The color on the paper must be rubbed off very
carefully with a soft rag. If it is too thick, it will transfer itself
coarsely to the stone. The red chalk may be put on the side of the paper
that has the drawing on it, or on the reverse. This is decided according
as the picture is to be on the stone in the same position as the
original or reversed. If the impression is to be like the original, the
drawing on the stone must be reversed; therefore in that case the
tracing-paper is coated on the same side as the drawing. This side is
laid on the stone, and the picture, which shows through, is traced.
In some cases it is good to transfer the drawing from the tracing
immediately to the stone without tracing it with the needle. In this
case, the paper is not coated with red chalk. The paper is merely laid
on the prepared stone, drawing face down, and put through the press. If
the drawing has been made with the chemical transfer ink, blackened with
lampblack or colored with vermilion according to need, it will transfer
itself to the stone. This will occur also in the case of a clean stone
prepared for pen drawing if the drawing is made with lead pencil or with
red chalk, wet or dry. Even the ordinary ink made from nutgall and
vitriol of iron will transfer if it contains a little sugar or gum, but
the paper must be well dampened and good pressure must be applied to the
press.
In the pen-drawing process, the stone must be cleansed of possible
surplus of color after the transfer. This is done by light rubbing with
sand. It is not necessary in other processes. Any surplus of color that
may have fixed itself to the stone is removed by gentle dusting with a
soft brush.
II
WASTE PAPER
This is used partly for cleansing plates, partly and chiefly as underlay
in printing.
If sheets are to be printed on both sides, usually a little of the first
impression off-sets on the underlay paper, and if it were used again at
once, it would off-set on the next impression. Therefore a fresh
underlay paper must be used for each impression of the second side.
This must not be coarse, for fear of causing unevenness or holes in the
leather in the printing-frame or in the so-called scraper-wood that
makes the impression. A good quantity of this must be on hand, that
fresh paper may always be available while the used paper is drying
again. Each sheet that has been used should be hung up at once, and not
more than three or four sheets should be hung over each other, to
facilitate the drying. A special appliance is needed for this as well as
for drying the impressions. A number of slats are fastened to the
ceiling, leaving a space under it of about two feet, and about one foot
distant from each other; and the sheets are hung on these with a pole
made for the purpose, such as may be seen in any printery.
III
PRINTING-PAPER
Not all kinds of paper are equally good for lithography. On the whole,
however, it may be assumed that this form of printing is very similar to
copper-printing and book-printing, and that the paper that is good for
these branches is suitable also for the stone, if only it does not
contain too many impurities, grains of sand and other substances that
make any considerable roughnesses. Such roughnesses, if considerable,
have an ill effect not only on the impression, but chiefly on the
leather in the printing frame. If the scraper is of wood, the leather
will suffer less, but there will be caused grooves in the scraper that
must be planed out again, because otherwise each following impression
will show a more or less plain streak. If the scraper is of metal, the
leather may tear or the stone itself may be injured if the foreign
substance in the paper is very hard. Therefore it is well to hold the
paper to the light before dampening or printing and to remove any
apparent defect of magnitude with a little knife.
Usually the paper considered most excellent for copper-plate work is
thick, tender, uniform paper, half-sized or not sized at all. It may be
the same for lithography. However, it must not be supposed that good
impressions cannot be obtained with sized paper. I have seen some that
were as good as, and even better than, impressions made at the same time
on unsized paper. Much depends on the dampening of the paper, on its
make, and chiefly on the manner of sizing it. On the best sized English
vellum paper, I have made blacker impressions than I could make on the
best Swiss copper-plate printing-paper, so that I had to use fifty per
cent less printing-color. On the contrary, in using an indubitably
genuine English vellum paper with a bluish tinge, which had been sized
only too well, I could not get good impressions despite all efforts. It
was very hard to dampen also. Every sheet must be dampened singly,
turned frequently and manipulated to smooth out the thousand
irregularities that are caused by the moisture. Equally difficult to use
were some sorts of genuine Holland paper, because they took color
reluctantly. If, however, the correct degree of moisture is attained,
if the paper takes it well, and, finally, if the color is right for it,
it can be used with thorough success.
I must mention a circumstance that may defeat all efforts of a beginner
should he try to use a certain kind of paper which is very handsome,
durable, very white, well sized, but a little rough and possessing an
odor somewhat resembling honey as well as urine. Sometimes it is called
_Kühnel_, and comes from a French factory. This paper has the property
of depriving the stone of its preparation, and consequently to smut it.
This paper can be used only for dry printing, where it does not require
any dampening at all.
It is said that this property of smutting the stone is due to the
chemical bleaching. Others ascribe it to a peculiar kind of size.
Perhaps it is both. The same defect is found in many sorts of colored
papers if there is much alum in the coloring-matter, or if the tints are
made from alkaline colors or those that contain soapy matter, or if it
has been smoothed with soap. This, however, is readily understood after
my explanation of the chemistry of the stone.
IV
DAMPENING THE PAPER
Dry paper may be used for printing. In certain work it is necessary, in
order not to spoil the paper. As a rule, however, paper is moistened in
lithography as well as in other forms of printing, to make it softer and
more receptive to the printing-color.
After what I have said of chemical printing, it would seem that, as
dampness is antagonistic to the reception of color, the moisture of the
paper would hinder, rather than aid, printing. But experience proves the
opposite. A damp paper takes color better than a dry one.
But this is not because damp paper is an exception to the rule. On close
study, we see that here, too, it only proves all that I said about the
stone.
Perfectly clean, and especially unsized paper, refuses color like the
prepared stone, when it has been wetted thoroughly so that it is
saturated. But here, too, mere water is not a complete preparation.
Under strong pressure it is forced away readily from the paper, the
printed places are dried and the color adheres. If the pressure is not
sufficient to force all the water away, the impression will be
imperfect. The tougher the printing-color is, the more will it resist
the dampness and the greater must be the pressure.
Experience has taught me the following:--
(1) Every paper not spoiled with fat will permit itself to be prepared,
like the stone, with water so that it will take no color. In the case of
entirely clean, unsized paper, water alone is sufficient. Mucous, gummy,
and acid substances increase its power. Unsized printed paper need
merely be dipped in water, laid on a stone, and coated with oily color,
and the printed parts will all take the color while the rest of the
paper remains white.
(2) Any great pressure will remove this preparation and the whole paper
will take color.
(3) The oil color must be very thin and fluid, because a tougher one
will take hold of the fibres of the paper and tear them off.
The foregoing experiences applied to the theory of the print itself lead
to the following conclusions:--
(_a_) The paper to be used for printing must never be too wet, because
the most powerful pressure could not remove the water sufficiently.
(_b_) Paper that is too wet is prone to adhere to the stone with its
printed parts, which are likely then to tear away easily, thus damaging
or ruining the work. This happens the more readily if the pressure be
not sufficient. If the scraper or the stone is not uniform and even, it
is very prone indeed to tear at the places subjected to the least
pressure, because there, where the water has not been sufficiently
squeezed away, the paper remains soft and fragile, while the pressure
still is great enough to grip the fibres of the paper.
(_c_) Therefore the paper must be only slightly dampened if the color is
very tough, partly to prevent tearing, partly to oppose no undue
obstacle to the reception of the color.
(_d_) Paper dampened too much stretches in printing and produces uneven
and dirty impressions.
(_e_) The quality of the water is not important so long as it is not
dirty or putrid, in which latter case it may infect the paper and rot
it.
(_f_) Just how much the paper must be dampened can be learned only from
experience, because papers vary very much and in the case of sized
papers it depends chiefly on the kind of sizing. On the average, we may
calculate one wet sheet to eight dry ones in sized papers and one wet
one to ten or twelve dry ones in unsized papers.
The following is the best way to dampen paper: Lay two or three dry
sheets on a straight board. Then dip a sheet into water. Let the water
drip off a little and lay the damp sheet carefully on the others. Now
lay eight or ten dry sheets on top of this. Then put on another wet one
and then eight or ten dry ones and so on till all the sheets destined
for printing have been so piled up. Put over all a board weighted with a
medium heavy stone plate. After half an hour increase the weight to
several hundredweight or squeeze the paper in a press. Leave it thus at
least twelve hours. Then it is generally ready for print. In aquatint it
must be dampened more, about six dry sheets coming to one wet one.
Very thoroughly sized paper is easier to moisten if each sheet, or at
least each second one, is wetted with a sponge.
Sometimes it is necessary to turn the dampened paper in order to remove
the creases. Separate the sheets into two piles and lay a few sheets
from one to the other so that the altered positions will press the
sheets flat again.
With many papers, especially the unsized, it is possible to use the
method of book-printers, who immerse a whole book in water and then lay
the sheets in two equal parts. This would be best studied at a
printer's. It requires much practice.
If dampened paper is permitted to lie some hours without being weighted
down, the margins will become too dry, and then there will be creases
during printing, which can be remedied only by a second dampening. The
reason is that dry paper is not so large as wet paper, so that the dry
margins form a kind of frame which is too small for the inner wet
portion.
In printing-processes that require many plates, and especially if the
sheets are large, only dry paper can be used, as otherwise the register
will be imperfect. To be sure, it can be done by using great care, but
too much practice and attentiveness is needed.
With the exception of the aquatint processes, good printing can be done
with dry but unsized paper. But the press must have twice or thrice the
pressure. This makes the printing more difficult and endangers the stone
if it is not thick.