Part 8 (1/2)
2. A _negative_ in which the whites of the original appear opaque, with clear gla.s.s to represent the lines and solids.
3. A _print_ which can be developed or inked up with a pigment sufficiently greasy in nature to transfer to the lithographic stone.
CHAPTER XVI
PHOTO-LITHOGRAPHY--_continued_
The Copy--Gradations of Tone--Sc.r.a.per 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 gla.s.s to take out the grain, and photographed by artificial light.
Sc.r.a.per 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 sc.r.a.per 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-sc.r.a.per 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 sc.r.a.per. Embossed lines only are the peculiar features of these boards, but variety of texture can be obtained by sc.r.a.ping these lines into dots.
Sc.r.a.per 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 sc.r.a.per 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 sc.r.a.per 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.
[Ill.u.s.tration: FIG. 29.--Reproduction of a drawing made on Gilby & Hermann's sc.r.a.per boards.]
[Ill.u.s.tration: FIG. 30.--Some sc.r.a.per 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 sc.r.a.per 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 gla.s.s representing the lines, dots, etc. These are all-important factors, and their influence upon the reproduction of the original can scarcely be over-estimated.
CHAPTER XVII
PHOTO-LITHOGRAPHY--_continued_