_The Calotype on the Sea-shore._--The great quantity of blue light
reflected from the sea renders calotyping in its vicinity much more
difficult than in the country; the more distant the object, the greater
depth has the blue veil which floats over it, and as a consequence of this
disproportion, if time enough is given in the camera to bring out the
foreground, the sky becomes red, and the distance obscured. After constant
failures with papers iodized in the usual manner, I made a number of
experiments to obtain a paper that would stand the camera long enough to
satisfy the required conditions, and the result was the following method,
which gives an intensity of blacks and half-tones, with a solidity and
uniform depth over large portions of sky, greater than I have seen produced
by any other process. Since I adopted it, in the autumn of 1852, I have
scarcely had a failure, and this success induces me to recommend it to
those who, like myself, work in highly actinising localities.
The object of the following plan is to impregnate the paper evenly with a
strong body of iodide of silver. I prefer iodizing by the single process,
and for this purpose use a strong solution of iodide of silver, as the
paper when finished ought to have, as nearly as possible, the colour of
pure iodide of silver.
Take 100 grains of nitrate of silver, and 100 grains of iodide of
potassium[4], dissolve each in two ounces of distilled water, pour the
iodide solution into the nitrate of silver, wash the precipitate in three
distilled waters, pour off the fluid, and dissolve it in a solution of
iodide of potassium, about 680 grains are required, making the whole up to
four ounces.
Having cut the paper somewhat larger than the picture, turn up the edges so
as to form a dish, and placing it on a board, pour into it the iodide
solution abundantly, guiding it equally over the surface with a camel-hair
pencil; continue to wave it to and fro for five minutes, then pour off the
surplus, which serves over and over again, and after dripping the paper,
lay it to dry on a round surface, so that it dries equally fast all over;
when almost dry it is well to give it a sight of the fire, to finish off
those parts which remain wet longest, but not more than _just to surface
dry it_.
Immerse it in common rain-water, often changing it, and in about twenty
minutes all the iodide of potash is removed. To ascertain this, take up
some of the last water in a glass, and add to it a few drops of a strong
solution of bichloride of mercury in alcohol, the least trace of hydriodate
of potash is detected by a precipitate of iodide of mercury. A solution of
nitrate of silver is no test whatever unless distilled water is used, as
ordinary water almost invariably contains muriates. The sooner the washing
is over the better. Pin up the paper to drip, and finish drying before a
slow fire, turning it. If hung up to dry by a corner, the parts longest wet
are always weaker than those that dry first. When dry pass a nearly cold
iron over the back, to smooth it; if well made it has a fine primrose
colour, and is perfectly even by transmitted light.
To excite the paper, take distilled water two drachms, drop into it four
drops (not minims) of saturated solution of gallic acid, and eight drops
(not minims) of the aceto-nitrate solution; mix. Always dilute the gallic
acid by dropping it into the water before the aceto-nitrate; gallate of
silver is less readily formed, and the paper keeps longer in hot weather.
If the temperature is under sixty degrees, use five drops of gallic acid,
and ten of aceto-nitrate; if above seventy degrees, use only three drops of
gallic acid, and seven of aceto-nitrate. The aceto-nitrate solution
consists of nitrate of silver fifty grains, glacial acetic acid two
drachms, distilled water one ounce.
Having pinned the paper by two adjacent corners to a deal board, the eighth
of an inch smaller on each side than it is, to prevent the solutions
getting to the back, lay on the gallo-nitrate abundantly with a soft cotton
brush (made by wedging a portion of fine cotton into a cork); and keep the
solution from pooling, by using the brush with a very light hand. In about
two minutes the paper has imbibed it evenly, and lies dead; blot it up, and
allow it to dry in a box, or place it at once in the paper-holder. For fear
of stains on the {135} back, it is better to place on the board a clean
sheet of ordinary paper for every picture. It is very important to have the
glass, in which the gallo-nitrate is made, _chemically_ clean; every time
it is used, it should be washed with strong nitric acid, and then with
distilled water.
To develop:--Pin the paper on the board as before; rapidly brush over it a
solution of gallo-nitrate, as used to excite. As soon as the picture
appears, in about a minute, pour on a saturated solution of gallic acid
abundantly, and keep it from pooling with the brush, using it with a very
light hand. In about ten minutes the picture is fully developed. If very
slow in coming out, a few drops of pure aceto-nitrate brushed over the
surface will rapidly bring out the picture; but this is seldom required,
and it will sometimes brown the whites. It is better, as soon as the gallic
acid has been applied, to put the picture away from the light of the candle
in a box or drawer, there to develop quietly, watching its progress every
three or four minutes; the surface is to be refreshed by a few light
touches of the brush, adding more gallic acid if necessary. Many good
negatives are spoiled by over-fidgetting in this part of the process. When
the picture is fully out, wash, &c. as usual; the iodide of silver is
rapidly removed by a saturated solution of hyposulphite of soda, which acts
much less on the weaker blacks than it does if diluted.
If the picture will not develop, from too short exposure in the camera, a
solution of pyrogallic acid, as DR. DIAMOND recommends, after the gallic
acid has done its utmost, greatly increases the strength of the blacks: it
slightly reddens the whites, but not in the same ratio that it deepens the
blacks.
After the first wash with gallo-nitrate, it is essential to develop these
strongly iodized papers with gallic acid only: the half-and-half mixture of
aceto-nitrate and gallic acid, which works well with weaker papers, turns
these red.
The paper I use is Whatman's 1849. Turner's paper, Chafford Mills, if two
or three years old, answers equally well.