Photo-Lithography

Before all things should be noted that the paper must be pure white and smooth, yet not strongly reflective and not too weak. Smooth white cards of medium thickness are the best to use. Since all lines of the drawing appear in the impression of the same colour, there is not only no purpose, but it may even be very disadvantageous to the reproduction when the draughtsman, in order to increase the artistic effect of his work, or to produce good perspective, etc., draws fine lines or other points in a lighter colour. The striving of the artist for effect, perspective, etc., so far as this is attained by lines or parts of a lighter colour, has for this process of reproduction no advantage, but, indeed, the disadvantage that by this the subsequent manipulations are rendered more difficult, the whole work will turn out more costly and finally less satisfactory.

Although from the present position of photography drawings in any desired colour can be reproduced, yet it is most advantageous if the originals for photo-lithographic reproduction are drawn with fine black matt ink on smooth white papers, and the principal point to which attention should be directed is that all lines, even the finest, should be a good black, and should be kept of the same strength of colour as the other parts of the drawing. The thick lines must be quite filled up like the shadow lines of a strong letter. Shading must be obtained by strong, fine running lines quite separate from one another. In this the single black lines must not be too strong, and the white spaces in between must not be too narrow, or otherwise when reduced in size the white interstices will disappear and will finally form a solid tone. The laying on of a tone or wash is not permissible, as even a light tone will appear in the reproduction as a black spot. It is not permissible also to draw on the same original with inks of different blackness or consistency, and even if a coloured ink be used the whole original must be prepared with one colour (red, dark blue, green, or brown), and that as intense as possible. When we start from the only true standpoint, that every reproduction should be a reflex of the original as true as possible, artistic effects have from this point of view no purpose, since the printer in printing with {22} one ink is not in a position to give grey lines as well as black, but can only give the appearance of everything in one colour only. He is, however, able to give with the strongest line the finest with their own characteristics, and can, therefore, in this direction attain the tonality of the original.

It is obviously, therefore, the artist’s duty to draw in one colour, and since for photographic reproduction black is the best, that is to say Chinese ink, he will do well to completely lay on one side all other artistic materials or effects. At the same time it should be noted that originals drawn in any other colour can be reproduced by photo-lithography, but if the drawing is to serve no other purpose than for reproduction it is best to prepare it in black.

A further important requirement is that the drawing be sharply and cleanly worked, and since the reproduction of a ragged or broken line cannot make a full smooth beautifully running line, they will appear in the reproduction in the same defective way, and then require at least tedious retouching or make the printing of the subject actually impossible. If it is necessary to cross the lines in the shadows this must be done with great care. The points of crossing must be clean and sharp, and the ink must not run. Too close or too frequent crossing of the lines should be avoided, and would produce a bad and different effect in the reproduction. Smudges or wrinkles in the original appear in the reproduction more intense and more vigorous, and therefore it must not be forgotten to carefully avoid these, also any tracing lines must be erased, without, however, damaging the ink lines or rubbing up of the paper.

Pencil and chalk drawings, assuming that they are cleanly executed, can be well reproduced by photo-lithography, only they ought not to be smudged or inked. Erasure marks on pencil drawings appear in the reproduction as smudgy spots.

Drawings of architecture for illustration or other purposes, after consideration of these remarks, can be well transferred without much trouble by photo-lithography on to stone or zinc.

In drawings of maps, plans, etc., there are still some rules to be observed besides the above. Boundary lines or mountain ranges with fine hatching, waterlines for large rivers, seas or lakes, as well as the introduction of figures, are better left out of the drawing, and can be afterwards drawn on the stone; they will then be cleaner and sharper. If all these details, however, must be introduced into the original drawing, they should be executed in a pale blue colour, which will not appear in the ordinary negative.

For plans with large letters it is better not to draw the latter, which are frequently a lot of trouble, but to employ the simpler plan of getting the titles, writing, legends, explanations, etc., printed by a book printer on paper of the same colour as the original, and stick them on the latter. The same method may be {23} adopted when preparing railway, postal, and telegraphic charts or maps with a lot of names or other titles, etc. The network of lines may be drawn with litho ink as suggested above, but the names of the stations, etc., can be printed with letterpress and stuck on in the proper places. Working in this way not only will much labour be saved, but at the same time sharper and more correct titles be obtained on the reproduction.

Any necessary instructions for carrying out the drawing should never be made on the paper with red pencil, but either with pale grey or pale blue. For this paper rubbed with indigo or graphite can be used or a scratched gelatine proof which has been rubbed with finely powdered milori blue.

With commercial drawings it frequently happens that ornaments are repeated. It is not necessary for the designer to draw all the ornamentation, which may frequently be very complicated, if it runs over the whole of the design. It is quite sufficient, according to the size or the number of times that the ornament occurs, for the artist to draw it twice or three times, or sometimes ten to fifteen times; the lithographer will duplicate it by transfer. This also applies if there is a border, or if there are any corner or centre pieces repeatedly used. It is quite sufficient to draw one-fourth of the frame or border, or with very complicated designs a complete corner, and to give the printer a rough sketch of the complete border. He will make the necessary impression on transfer paper by photo-litho transfer on the stone; he will also reverse the drawing from right to left, join up the different parts, and thus construct the whole border. This applies also to the corner and centre piece.