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

pressure sideways on the conical Japanese brush, and the result was perfect.
The same bamboo-stem painted in a finicky fashion, with a multitude of
touches, would have produced quite an inferior effect. The blacks would
not have been the same, and the fluid, watery sensation between the light and
shade would not have been there.
Now, what is important in a wash-drawing is just as important in a gum-
print. Fine tones, true rendering of values, etc., are no more the property
of one process than of another; they are evolved from the brain and hand of
the artist who is using it. A beginner in gum ought to have it impressed
upon him that the first complete replica he will obtain with his process (unless
by some extraordinary stroke of luck) will show the worst side of it and will
be unfit for publication. He must learn that the finest composition will not
be worth much, if it be printed in dirty black with values placed haphazard
and with a mangy, old-Italian fresco surface lacking even the excuse of
antiquity. One must have worked at gum-bichromate for some time to
realize the numberless variety of results produced by degrees of over-and
under-printing and by varied thickness of the film. From these the gum-
printer must learn how to choose. He will not learn this in a day nor will
complicated formulæ teach him.
It is impossible in an article of the length of the present one to go into
every technical detail of the process, but I think that two sound principles
can be given as a basis for personal experiments:
First: A proper smoothness of film is absolutely necessary. This
can be obtained only by using a sensitive color-mixture of proper thickness.
The degree of this thickness is dependent upon the roughness of the
paper. When the lines and ridges made by roughly smearing the mixture
over the sheet of paper can be easily smoothed down with brush No. 2, it is
of the proper thickness; but when these ridges resist or when no ridges are
left after the smearing, the mixture is too thin. Avoid this last error, above
all, by using thick gum stock which will allow you to thin down your
sensitive color-mixture with bichromate solution and to secure a strong film,
good half-tones and shorter exposure.
Secondly: Bear in mind that absolutely insoluble film can not possibly
give any depth in the shadows. Once dry, an overexposed picture, though
it may have appeared quite beautiful while it was wet, will be gritty, dull and
sombre, much uglier than an ordinary bromide print. It is indispensable that
the exposure should be such as to let the developing-water permeate every
shadow of the gum-picture right down to the paper. There ought always to
be a slight tendency to running, a strong one if a water-color effect is intended.
In the case of brush development proper, the exposure must be carried
further, but never so far as positively to tan the film in the blacks. Of
course a complete image will always be obtained by rubbing—whatever is
the state of the film—but we are talking of pictures.
In fine, the practical gum-process theory is thus brought down to two
lmportant factors: proper thickness of sensitive mixture and proper length
of exposure. It will be easily understood that both these factors are too

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