1 1/2 ounces.
Bichloride of Mercury,...........................
1 1/2 "
l 1/2 "
To reduce the intensity of the negative, flow over (after clearing and washing) with this solution. Then wash and flow with strong cyanide of potassium, wash and repeat as often as necessary, to reduce to proper intensity. Then flow with gelatin, and dry, and retouch finely. Now take another glass, perfectly clear, and flow over with pure balsam of fir; heat both negative and other glass, and then place them together; use two pairs of wooden pincers to fasten them. See that no air remains between the glasses, and finish by pasting gum paper around the edges. By following this process no one need have any trouble to get fine solar negatives of any intensity, as you can reduce your negative as far as you wish, and stop. - N. P, Harrington.
I will try and give you something that is practical in the way of a solar-printing propose that has no patent, and is equal to the best. It takes less preparation, and the same negative is just as good for contact - printing afterwards as ever. In this process any contact negative may be used. Made in the ordinary way and nicely retouched, it is all ready for use with the following directions: Take the negative and with a piece of chamois skin carefully clean off all finger-marks, being careful not to disturb the retouching; now take another glass of the same size, free from scratches and blisters, clean it thoroughly; next get a piece of India-rubber tubing about one - eighth of an inch in thickness, lay the rubber tube on the negative all around the edges, except a small space at one end, leaving an opening between the two ends of about one - half inch; now lay the other glass on to the rubber and bind the two together, this will leave a space about one - eighth inch between; now at the end where you have left the open space, pour in pure glycerin until it is filled up; now place your negative in the proper position in the solar, and it is ready for printing, and will make a soft and delicate print in much less time than it would take otherwise; the glycerin coming in contact with the retouching, obliterates all marks of the pencil and makes it more transparent, and the result is a fine, soft photograph, full of detail and roundness, often surpassing the contact-print. After the negative has done its work, separate the glasses and wipe off the glycerin, and your negatives are all ready to make contact - cards again. In placing the negative in the solar, put it in the usual way, the retouched surface facing the paper, and print through the glycerin, unless you wish to make a reversed picture. The glass does not seem to become near as hot in printing as by the old process, thereby lessening the danger of breakages. - E. P. Libby.
350. So far it would seem that the only method of making enlargements is by means of solar or sunlight, but such is not the case. The ordinary magic lantern may be made to serve in place of the sun and provide artificial light of sufficient intensity to answer every purpose. And again, light through the camera may be dispensed with and a tracing apparatus be made to do when necessity or convenience compels it. The Philadelphia Photographer must now be called upon to give up some of its information to tell us how.
When printing from a coarse, hard negative, one that is badly varnished perhaps, and a good clean and soft print is desirable, or a print from any solar negative is wanted that will need no spotting, proceed as follows: Print about half done, then lay over the unfinished print a piece of ground-glass same 6ize of the print, and always with the ground side towards the condenser, and continue printing. This will have a softening effect, without affecting the sharpness; ordinary blemishes disappear as if by magic, and a good print is made possible by this means from negatives that would ordinarily yield bad results. Try it. - C. A. Zimmerman.
350. Drawings of the needful apparatus for solar printing by artificial light are as follows: A box, G, surmounted by a chimney, H, or, in other words, the box of a magic lantern, includes the blow-pipe and other apparatus necessary for producing the light. A triple system of condensers, say five inches in diameter, is placed laterally upon the box at a. To this the parts of a solar camera described are to be attached in the manner shown in the cut, so that the negative is at o, and the amplifying objective is at d. The blow-pipe should have its luminous point exactly in the focus of the condensing lenses. For this purpose the objective, D, is used as a guide, the luminous cone passing freely through it. By advancing the blow-pipe towards the interior lens, or by drawing it back, the brilliancy of the field may be considerably varied, and it is therefore necessary to pay particular attention to this point. As the luminous point of the blowpipe is variable in the direction of the height, it is by means of the rack and pinion attached that the luminous point may always be brought on the axis of the apparatus. This apparatus is arranged for the oxyhydrogen light, but an oil sciopticon may be adapted to the same kind of work, acting more slowly, of course.
351. A great many photographers afford a solar camera, and an apparatus that would enable then to have some of its advantages will doubtless be of service to them. All photographers, after the careful study of Gihon's Photographic Colorists' Guide, can make good use of their spare time in crayoning , and inking or coloring enlargements from their negatives. The first step is to procure the enlarged sketches of the picture you propose to make. This can be done by means of the apparatus which is described below by the inventor, if you have not a solar camera.
The next figure represents the general arrangement of the apparatus in use, including the gas - bags for the gases used, and all the connections necessary. Such an enlarging apparatus as this may also be used with artificial light for making, with wet collodion, large negatives on glass from a small positive on glass, which, requires an exposure of but a few seconds. - Da. D. von Monckhoven..