For these plates any one can easily make a temporary drying-box by standing the racks on a shelf in the firegrate, and covering a thick cloth over the front of the fireplace in the same way as a sweep does when sweeping a chimney. Then place 2 or 3 little pieces of wood on the floor to form little inlets between them for the air to pass between the floor and the cloth; a piece of fine muslin thrown over the racks would keep any dust, etc, from the plates.
To print, the plates are put in a printing-frame against the negative, the same as a piece of albumenised paper. One can judge how deep to print by opening one-half of the printing frame back, and by looking down on the back of the transparency; when the whole of the high lights of the picture are just tinted, it will be printed deep enough.
Fuming the plates with ammonia is a great improvement in every way. Do this by standing a few of the plates against the sides of a small box. Then pour a few drops of ammonia onapiece of blotting paper, put it in the bottom of the box, which is closed for a short time, and the plates are then ready for printing.
The great difficulty with these plates, until recently, has been with the toning. The action was not only slow, but I could not get the warm brown or sepia tones I was trying for. I tried a number of different toning formulas, but all had the same action, though some bleached more than others. At last it struck me that I had a slight excess of acetate of soda in the film, so I tried the gold alone, and then got the tones I wanted, and far more quickly. The formula was:-
In a clean developing dish I took of the
Chloride of gold solution. 8 minims.
Water . 1 oz.
Hyposulpbate of soda 1 oz.
Water.... 5 oz.
for about 15 minutes, and again well washed.
Lately I found I could tone the plates in about 1/5 the time taken by the above bath, by adding acids to the gold before neutralising with the whiting. The bath was made as follows:
Gold solution . 8 minims.
Hydrochloric acid 2 „
Nitric acid. 1 „
Water... 1 oz.
Whiting . 2 - 3 gr.
This bath toned the plate very rapidly and equally, but requires the plate to be rather more deeply printed than when the acids are not used. I hare not had time to try any comparative test with prints from the same negative, as to which bath gives the best tones and results, and can only speak now as to the rapidity. It is better not to print in direct sunlight if the sun is at all warm, as the warmth sometimes causes the films to stick slightly.
There are two uses for these plates, besides lantern slides and transparencies. By printing less deeply and backing with tinted or drawing paper (film to the paper), they do capitally for producing photo-crayons. But for professional photographers, their great use will be in the reproduction of negatives, as one can not only see how deep to print with both the transparency and the second negative, but parts can be shaded during printing to get details in other parts which may be too dense in the original negative.
It will be also seen, however, that any amount of " dodging " can be done. The transparency can be retouched as required, any shadows which print too heavy can be reduced in the same way as too dense negatives are locally reduced. Then we can do any amount of double printing, printing in clouds, etc., on the transparency. The name of the view can be painted on it without having to reverse the letters. We can vignette or mask when printing from either the original negative or the transparency. In fact, we can build up, so to speak, the picture on the transparency as we require it, because we can see what we are doing. And when it is perfect, we have only to print by contact a second or any number of negatives from it, which negatives can be printed from on to paper without any trouble of vignetting, etc., for each separate print. And to my mind, Henderson's discovery of the use of acetate of silver with the chloride in the gelatine film for contact printing will lead to very important results, in the aid it will be, practically, to photographers in their every-day work. (H. S. Starnes.)
(a) Use transparent colours, namely, Prussian blue, gamboge, carmine, verdigris, madder brown, indigo, crimson lake, and ivory black, with the semi-transparent colours, raw and burnt sienna, and vandyke and cappal brown, thinning oil colours with ordinary megilp to a degree just sufficient for proper working, and using for a medium for laying on the first coat of water colours gelatine thoroughly dissolved and hot. When perfectly dry this coat can be shaded and finished with water colours mixed in the ordinary way with cold water; but the manipulation of the added colours must be gentle, so as not to disturb the layer first put on the glass. A thin coat of the best mastic varnish heightens the effect of shades painted in water colours, but oil colours require no varnish.
(6) Having failed in getting results to please myself by dabbing, stroking, and many other dodges, I have now succeeded in getting perfect gradation of tone by pouring on a filtered solution of colour, previously ground up with "medium," in an agate mortar. Pour it on very dark at the top of the picture and flow it down to the horizon, then back again slowly, and allow it to drain off at the edge; when the proper depth is attained, blot off the drainings from the edge; when dry, the outline of the horizon is easily obtained sharp by rubbing off the paint which has run over the border with a fine paper stump. Should any dust settle in spite of all precaution, make your clouds at the faulty part, thus getting rid of specks. (G. Smith.)