_Dr. Diamond's Services to Photography._--SIR, We, the undersigned amateurs
of Photography in the city of Norwich, shall be obliged if you will
(privately, or otherwise, at your own discretion) convey to DR. DIAMOND our
grateful thanks for the frankness and liberality with which he has
published the valuable results of his experiments in the pages of "N. & Q."
We have profited largely by DR. DIAMOND'S instructions, and beg to express
our conviction that he is entitled to the gratitude of every lover of the
Art.
We are, Sir,
Your obedient servants,
T. LAWSON SISSON, Clk., (Edingthorpe Rectory).
THOS. D. EATON.
JOHN CROSSE KOOPE.
JAMES HOWES.
T.G. BAYFIELD.
G. BROWNFIELD.
HENRY PULLEY.
W. BRANSBY FRANCIS.
J. BLOWERS (Cossey).
BENJ. RUSSELL.
[Agreeing, as we do most entirely, with the Photographers of Norwich in
their estimate of the skill and perseverance exhibited by DR. DIAMOND
in simplifying the collodion and paper processes, and of his liberality
in making known the results of his experiments, we have great pleasure
in giving publicity to this recognition of the services rendered by DR.
DIAMOND to this important Art.]
_Simplification of the Wax-paper Process._--At a late meeting of the
Chemical Discussion Society, Mr. J. How read the following paper on this
subject:--
"The easiest way of waxing the paper is to take an iron (those termed
'box-irons' are the cleanest and best for the purpose) moderately hot, in
the one hand, and to pass it over the paper from side to side, following
closely after it with a piece of white wax, held in the other hand, until
the whole surface has been covered. By thus heating the paper, it readily
imbibes the wax, and becomes rapidly saturated with it. The first sheet
being finished, I place two more sheets of plain paper upon it, and repeat
the operation upon the top one (the intermediate piece serving to absorb
any excess of wax that may remain), and so on, sheet after sheet, until the
number required is waxed.
"The sheets, which now form a compact mass, are separated by passing the
iron, moderately heated, over them; then placed between folds of bibulous
paper, and submitted to a further application of heat by the means just
described, so as to remove all the superfluous wax from the surface, and
render them perfectly transparent--most essential points to be attended to
in order to obtain fine negative proofs.
"I will now endeavour to describe the method of preparing the iodizing
solution.
"Instead of being at the trouble of boiling rice, preparing isinglass,
adding sugar of milk and the whites of eggs, &c., I simply take some milk
quite fresh, say that milked the same day, and add to it, drop by drop,
glacial acetic acid, in about the proportion of one, or one and a half
drachm, fluid measure, to the quart, which will separate the caseine,
keeping the mixture well stirred with a glass rod all the time; I then boil
it in a porcelain vessel to throw down the remaining caseine not previously
coagulated, and also to drive off as much as possible of the superfluous
acid it may contain. Of course any other acid would precipitate the
caseine; still I give the preference to the acetic from the fact that it
does not affect the after-process of rendering the paper sensitive, that
acid entering into the composition of the sensitive solution.
"After boiling for five or ten minutes, the liquid should be allowed to
cool, and then be strained through a hair sieve or a piece of muslin, to
collect the caseine: when quite cold, the chemicals are to be added.
"The proportions I have found to yield the best results are those
recommended by Vicomte Veguz, which I have somewhat modified, both as
regard quantities and the number of chemicals employed. They are as follow:
385 grains of iodide of potassium.
60 " of bromide.
30 " of cyanide.
20 " of fluoride.
10 " of chloride of sodium in crystals.
1½ " of resublimed iodine.
"The above are dissolved in thirty-five ounces of the strained liquid, and,
after filtration through white bibulous paper, the resulting fluid should
be perfectly clear and of a bright lemon colour.
"The iodized solution is now ready for use, and may be preserved, in
well-stopped bottles, for any length of time.
"The waxed paper is laid in the solution, in a flat porcelain or gutta
percha tray, in the manner described by M. Le Gray and others, and allowed
to remain there for from half an hour to an hour, according to the
thickness of the paper. It is then taken out and hung up to dry, when it
should be of a light brown colour. All these operations may be carried on
in a light room, taking care only that, during the latter part of the
process, {94} the paper be not exposed to the direct rays of the sun.
"The 'iodized paper,' which will keep for almost any length of time, should
be placed in a portfolio, great care being taken to lay it perfectly flat,
otherwise the wax is liable to crack, and thus spoil the beauty of the
negative. The papers manufactured by Canson Frères and Lacroix are far
preferable, for this process, to any of the English kinds, being much
thinner and of a very even texture.
"To render the paper sensitive, use the following solution:
150 grains nitrate of silver crystals.
3 fluid drachms glacial acetic acid, crystallizable.
5 ounces distilled water.
"This solution is applied in the way described by Le Gray, the marked side
of the paper being towards the exciting fluid. The paper is washed in
distilled water and dried, as nearly as possible, between folds of bibulous
paper. It should be kept, till required for the camera, in a portfolio,
between sheets of stout blotting-paper, carefully protected from the
slightest ray of light, and from the action of atmospheric air. If prepared
with any degree of nicety, it will remain sensitive for two or three weeks:
indeed I have seen some very beautiful results on paper which had been kept
for a period of six weeks. At this time of year, an exposure in the camera
of from ten to twenty minutes is requisite.
"The picture may be developed with gallic acid, immediately after its
removal from the camera; or, if more convenient, that part of the process
may be delayed for several days. Whilst at this section of my paper, I may,
perhaps, be allowed to describe a method of preparing the solution of
gallic acid, whereby it may be kept, in a good state of preservation, for
several months. I have kept it myself for four months, and have found it,
after the lapse of that period, infinitely superior to the newly-made
solution. This process has, I am informed, been alluded to in photographic
circles; but not having seen it in print, and presuming the fact to be one
of great practical importance, I trust I shall be excused for introducing
it here, should it not possess that degree of novelty I attribute to it.
"What is generally termed a saturated solution of gallic acid is, I am led
to believe, nothing of the kind. In all the works on photography, the
directions given run generally as follow:--'Put an excess of gallic acid
into distilled water, shake the mixture for about five minutes, allow it to
deposit, and then pour off the supernatant fluid, which is found to be a
saturated solution of the acid.'
"Now I have found by constant experiment, that by keeping an excess of acid
in water for several days, the strength of the solution is greatly
increased, and its action as a developing agent materially improved. The
method I have adopted is to put half an ounce of crystallized gallic acid
into a stoppered quart bottle, and then so to fill it up with water as
that, when the stopper is inserted, a little of the water is displaced,
and, consequently, every particle of air excluded.
"The solution thus prepared will keep for several months. When a portion of
it is required, the bottle should be refilled with fresh distilled water,
the same care being taken to exclude every portion of atmospheric air,--to
the presence of which I am led to believe, is due the decomposition of the
ordinary solution of gallic acid.
"It will be needless to detain you further in explaining the
after-processes, &c. to be found in any of the recent works on the
Waxed-paper Process, the translation of the last edition of Le Gray being
the one to which I give the preference."
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