Camera Work: A Photographic Quarterly (1904 (Heft 7))

variable to be made the subject of a formula; the thickness of the mixture being
governed by the nature of the paper to be coated, and the exposure by the
ordinary photographic conditions, to which must be added for gum-bichromate
the color of the film, its degree of thickness and the varying percentage of
chromic salts in its composition.
Of course the use of ready-coated paper will do away with most of the
uncertainties of the process, but this means uniformly prepared paper and
consequent uniformity of quality and flavor in the results. Although I may
be wrong, I do not think that any paper that will float on a bichromate bath
without melting can be made with pure gum. On the other hand, in all the
samples of commercially prepared paper I have experimented with I have
detected the presence of gelatine in some form or other. When this is
present one must bid farewell to all the water-color scale of effects, which I
have always found it impossible to secure with pure gelatine, such as we find
in the ozotype process, gum-gelatine or other such compounds. Pure gum,
on the contrary, will allow of a wide range of effects, from the delicate washed-
out quality of water-colors to the strong accents of etching or engraving.
The danger of ready-made gum-bichromate paper lies in the extreme facility
with which certain gloomy effects may be produced over and over again.
The beginner may thus fall into a rut and thus add another inexperienced
disciple to the school of low tone which, to be properly rendered, demands
a profound knowledge of relative values that very few photographers
possess.
From my own point of view I find that home-made paper, even with
its greater uncertainties, is infinitely more interesting to work than the other.
It is astonishing how differently the coating will behave under development,
according to the grain, the texture and the thickness of the paper. The final
effect differs in each case, and there is an inexhaustible supply of queer
papers in the market, besides the well-known brands, most fascinating
to experiment upon. By all means coat your own paper, and you will find
ample reward for your pains. The consideration of expense also favors
home-coating.
Another practice we hear but little about from gum experts, at least from
its practical point of view, is double printing. It is generally represented as
a sort of distinct process, invented by and peculiar to the Germans, but it
may be used occasionally as a corrective without any of the complicated
paraphernalia of the redoubtable " Gummidruck." I have done this work
myself, now and then, and have saved several underexposed prints that way.
But these must be cleanly developed with pure whites, and without granular
effect. The final picture will thus be composed of double-printed shadows
and single-printed half-tones— a strong picture without harshness. Also the
second coating may be applied locally, the uninteresting parts being left just
as they are, half washed away and a quantity of fruitful combinations may
thus be evolved. For brown or light sepia tones double printing is extremely
helpful, for it is most difficult to get strong oily pictures with such transparent
colors as Van Dyck brown, bistre, ochre and the series of yellows. In this
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