PHOTO-LITHOGRAPHY--_continued_
The Copy--Gradations of Tone--Scraper Boards--Description
and Effect--Shading Mediums--Crayon Drawings--Half-tone
Copy.
It has already been pointed out that well-defined modelling is most
desirable in the original copy. To secure this a considerable degree of
artistic perception and discretion, as well as manipulative skill, is
requisite. In photo-process work it is almost impossible to produce
artistic effects from an indifferent or unsuitable copy.
Pen-and-ink sketches and wash drawings are entirely under the control of
the artist, and characteristic effects are chiefly due to bold and
vigorous conception and skilful drawing. Few photographs are suitable
for photo-mechanical reproduction without some previous preparation.
Accentuation or modulation of the high lights and shadows will in all
probability be necessary to secure a sufficient contrast of light and
shade. The middle tints may require but little attention, unless it be
to work down any tendency to abruptness in the gradations of tone. A
bold and well-defined silver print usually copies well when clamped
between two pieces of glass to take out the grain, and photographed by
artificial light.
Scraper boards offer most remarkable possibilities for black and white
and half-tone sketches. A careful examination of Fig. 29 will serve to
demonstrate their peculiar fitness for process drawing. A light wood
pulp board forms a convenient base upon which a thick coating of white
composition is laid. Black ruled lines are printed on this surface, and
lines of a similar texture are embossed at right angles to them. Some of
the characteristic effects which can be produced on this board by the
use of the crayon and scraper are suggested by Nos. 6 and 7, Fig. 30.
No. 8 gives a stipple which is both printed and embossed. No. 9 is a
plain board upon which pen-and-scraper effects alone are produced.
Drawings in pen and ink, on Nos. 10 and 11 patterns, may be effectively
handled by a free and skilful use of the scraper. Embossed lines only
are the peculiar features of these boards, but variety of texture can be
obtained by scraping these lines into dots.
Scraper board sketches almost invariably represent a maximum of effect
with a minimum of work, and for this reason alone such an adaptable and
simple medium should soon win its way into general favour.
Their merit, however, is not confined to this one point. They provide
almost unrivalled copy for photo reproduction, and can therefore be
applied to a variety of purposes. Even a cursory glance at the scraper
board sketch on page 91 will reveal many points of interest and value
which a more careful scrutiny can scarcely fail to emphasise.
Small patches of scraper boards can be introduced into process drawings
of any description, and brilliant results be secured thereby. In such a
manner clouds, waves, foliage, and a variety of other effects can be
introduced.
Shading mediums are already well known to lithographers, yet it is
doubtful if their usefulness for the amplification of sketches or
process drawings is fully appreciated. They offer almost endless
combinations of texture and tint, and are therefore most useful and
valuable accessories in the hands of a resourceful artist.
[Illustration: FIG. 29.--Reproduction of a drawing made on Gilby &
Hermann's scraper boards.]
[Illustration: FIG. 30.--Some scraper board textures.]
Many artists favour crayon work on a grained paper, adopting a
broad sketchy treatment in liberal proportions, so that in the
subsequent reduction the freedom of the original will be toned down just
sufficiently to enhance the picturesque and artistic value. Drawings
made on scraper boards, grained papers, or by the aid of shading
mediums, are photographed and reproduced by the ordinary line method. In
making sketches for "half-tone" photo-mechanical reproduction it must be
remembered that, as far as photo-lithography is concerned, it is
impossible to accentuate effects by what is known as "fine etching" when
applied to photo-engraving. A negative for photo-process work of any
description should be absolutely perfect in every respect. The whites of
the copy in the negative should be of an absolutely opaque black,
showing clean, sharp edges, with clear glass representing the lines,
dots, etc. These are all-important factors, and their influence upon the
reproduction of the original can scarcely be over-estimated.