Etchings can, as a rule, only be reproduced with the aid of a cross-grained screen, and the same applies to photogravures, although the latter will seldom be required.
All tone or painted originals, such as wash or sepia drawings, photographs from nature, collotypes, photogravures, water-colours and oil-colours can only be reproduced by photo-lithography by the interposition of a screen when making the negative, or by a process in which the breaking of the tone is effected independently of the photographic negative, and which will be described later on.
With old photographs which have faded it is as well to increase the lights and shadows by painting.
(E.) SIZE OF THE REPRODUCTION.
A question frequently asked is, “Of what size should a drawing be made in order to obtain a good photographic reproduction?” This question cannot be precisely answered, for a good deal depends upon the object itself, and on the kind of drawing.
It may be generally said, however, particularly as regards pen and ink drawings on smooth paper, that they should never be smaller, only very rarely of the same size; they should be drawn one-third or one-half larger generally. The artist can execute fine details more easily and precisely on a large drawing than on a small one.
The enlarged reproduction gives any faults or mistakes which may happen to be in the drawing in proportionately larger size quite independent of the fact that an enlarged reproduction is always somewhat rough and ordinary. Reproduction in the same size reproduces the faults the same size as they exist in the drawing; the reduction, however, also reduces the failings of the drawing if it cannot also absolutely remedy the same. The reduced copy has always something finer and more delicate. The degree of reduction must be kept in mind, and the drawing be done with this in view.
If a drawing is executed very finely and full of detail, and, besides that, contains very small lines of drawing or titles, they do not gain in reduction, but the opposite; they lose, as much that in the drawing appears plain and distinguishable becomes by strong reduction indistinct and unrecognizable, or appears to the eye as a tone. {29}
Individual cases, in which for specimen purposes or to show how far reduction can go, many times linear, five, six, to ten times, cannot be taken into consideration, although the effect is usually well attained.
It should also be observed that the drawing must be considered not only as regards its size, but also the strength of the lines and tones generally for reduction; this specially applies as regards the tones. By reduction the tone gradations are compressed, the picture becomes poorer in tones, and although, theoretically considered, light and shadow, that is to say black and white, are actually distributed in the same ratio as in the original, yet the reduced image appears proportionately darker and loses in artistic effect.