The Photographic News.
Vol. 10, No. 415.
August 17, 1866. p.394
BY M. CAREY LEA. *
INTO THE CIRCUMSTANCES UNDER WHICH SILVER IS FOUND IN
THE WHITES OF ALBUMEN PRINTS.
THE last two years have witnessed the most serious assaults that
have ever been made upon silver printing, and for a time with every
prospect of immediate success. Nevertheless, the old process is just
as fixed as ever, and there seems as yet little prospect that any of
the novelties so vaunted will secure even a humble share of the
work. Not that I have the least disposition to undervalue carbon
printing. I earnestly hope to see the day come when it will entirely
replace chloride printing. Mr. Swan and Mr. Pouncy have produced
some specimens of work of beauty so extraordinary, as, in my
opinion, to have surpassed the best silver printing. And some
specimens of Mr. Woodbury's relievo printing are extremely good. But
something easier, simpler, and more certain will have to be thought
out before the old method becomes antiquated. So long as it does
not, it will be a matter of unceasing regret that any doubt should
exist as to the perfect permanency. To purchase an exquisitely
beautiful photograph, and, after a time, to see that fatal
yellowness stealing over the high lights, and to know that its final
destruction is only a question of time, is a real vexation. Fifteen
years ago I purchased, when abroad, a number of Roman photographs,
not one of which is now worth the paper on which it is printed; and
every one has had similar experience.
It, therefore, is clear that the two directions in which study
can be most profitably directed for the advancement of photography,
are, in the simplification of carbon printing, and in the
determination of all the causes of deterioration to silver
It is a well-known fact, though only lately ascertained, that
silver exists in the whites of albumen pictures. I have carefully
studied the conditions of its presence, and, without being able to
make so satisfactory a report of results as I could wish, I hope to
have done something towards extending our knowledge in this
Before proceeding to detail the results of individual
experiments, I may mention one general fact. It has been asserted
that the existence of silver in the whites was due to the action of
faint light, passing through the darkest parts of the negative--light
too faint to visibly darken the chloride of silver, and thus impair
the whiteness of the high lights. I have disproved this in the
following manner: A piece of albumenized paper was sensitized at
night, dried, washed, and fixed, without any exposure, under a
negative. It was, of course, snow-white. Tested with sulphydrate of
ammonia, it gave indications of silver, just as well-marked as other
pieces exposed under a negative, and fixed and toned in the usual
way. There can exist, therefore, no doubt that the presence of
silver in the whites is owing to a combination formed at the time of
sensitising, and that it has nothing to do with the exposure.
I have also remarked another fact which has its importance, and
which, if not duly borne in mind, may lead to erroneous conclusions.
It is, that even dilute sulphydrate of ammonia will make a very
evident mark upon albumenised paper which has never been sensitised,
and which consequently does not contain a trace of silver. While
wet, this mark is yellowish, and so exactly simulates the appearance
produced when a faint trace of silver is present, that even a
careful observer might be deceived. Even after drying, the mark does
not disappear. The yellowish colour of course is gone, but there
remains a dead mark that contrasts with the brilliance of the
general albumen surface, and this all the more strongly, as the dead
mark is surrounded by a bright border, brighter even than the rest
of the albumen surface.
When testing, therefore, in this manner, it is necessary to let
the mark made by sulphydrate of ammonia become completely dry before
judging of it; and also to bear in mind, in the case of very faint
marks, that their intensity is increased in appearance by the great
alteration of surface caused by the reagent.
I shall next proceed to give the comparative results in the
examination of the condition of the whites in a great many different
tonings. To make the results fairly comparative, the following
method was resorted to. A large negative, highly intensified, so
that the high lights were perfectly protected, was printed. A number
of different toning baths were prepared, and got into working order
together. The print was washed, then cut up, and different pieces
were toned in the respective different baths, were fixed with
hyposulphite of soda, and, after drying, were tested with
hydrosulphate of ammonia. The specimens thus obtained--some as far
back as last winter, and others at various times--were carefully
indorsed and noted, and are now before me as I write. In all cases
when the contrary is not stated, the prints were made on
- Toned in the citrate of gold bath. Fixed in hypo.--. A
camel's-hair pencil or clean pen dipped in dilute sulphydrate of
ammonia, and drawn over the whites of this specimen, left a clear
buff mark of sulphide of silver.
- Toned with benzoate of gold as described by me.-- Result the same
as the last.
- Sulphur toning (trithionate toning), obtained by adding chloride
of lead to hyposulphite of soda.--This toning, with or without the
addition of gold, is sometimes used still for obtaining intense
blacks upon plain paper. It is, of course, not to be recommended,
and is included here for greater completeness. Here a larger amount
of silver seems to be left in the albumen, for the application of
the sulphydrate caused a much deeper mark than in the
- The next trial was made with the well-known old toning and
fixing bath of hyposulphite of soda, to which gold has been added.
On treating the white with sulphydrate of ammonia, indications of
silver were obtained, but much less than in any of the preceding.
The streak, in fact, was pale yellow.
- The lime toning.--The indications of silver in this case were
- Alkaline chloride toning gave results not varying materially
from the last.
The trials in three of the above tonings were repeated
subsequently. The citrate and benzoate of gold gave the same results
as above stated. The third was the fixing and toning bath of hypo
and gold. In the trial above given, it is mentioned that the mark,
in its case, was much paler than in the others. In the repetition, a
print was obtained of which the whites were perfectly free from
silver. After the mark of sulphydrate was dry, it could not be