363. In some parts of Europe, and to a more limited degree in America, pictures known as "collodion transfers" (given also the trade name of "megatype") have been introduced with some success. A negative is made in the usual way, and from it an enlarged collodion positive is made, the film of which is transferred to a sheet of gelatinized paper, usually, and finished in India-ink or oil-color. "Without being thus finished, unless delicately toned, they are gray and unpleasing in color, and have no quality to recommend them.

Precautions against Damp. - To secure the most brilliant results, the sensitized paper before, during, and after its exposure to light, should be kept as dry as possible. It is of the first importance that the printing-frames and pads be quite dry. Between the sensitized paper and the pads a thin sheet of vulcanized India-rubber may be placed with great advantage. The effect of damp is seen in a want of vigor, a general muddiness of tone, and, where the sensitized paper has been exposed to its influence for some days, in the impaired purity of the whites. Paper in a damp state takes much longer to print than dry paper.

363. The principle is just the same as that of the reflecting solar camera without the reflector or condenser. A lone - focus obiective is, perhaps, the best for full figures. The camera-box should be about fifteen inches square and eighteen inches long. Pig. 109 will make it plainer, f is a board fifteen inches long, to which the box is fastened; A is the easel, which slides on the board to or from the lens, according to the size you want to enlarge; b is a rod of wood, or iron is better, which is fastened to the carrier inside the box, into which you slide your negative. You focus (after your easel is far enough away to give the size you want) by moving the negative-rack by means of the rod B to or from the lens inside, until your image is sharp on a glass covered with white paper, placed on a ledge on the easel; remove this glass, and place your sensitized plate in the same place, and time about one minute, or according to the density of your negative; of course, there must be no white light in the room. - J. H. Folsom.

Fig. 109.

Phototypes ,Platinotypes Etc.

Phototypes ,Platinotypes Etc.

364. Artificial light may be used by those who have a magic lantern at their service and not enough time while the sun shines to do the work. The ordinary both may be used, though it is just as well to reserve a bath for this use only. Not that it is necessary in order to improve the trans-

364. My transfers are made upon waxed glass developed with Iron, not toned, and fixed with cyanide of potassium, transferred upon albumenized or gelatinized paper, according to the results required; the results are very clean, the tone a warm purple black, richer and brighter than I have ever got by a process which requires toning. The glass upon which the enlargement is made should be very perfect, without bubbles or scratches, waxed in the same manner as for carbon printing by double transfer, coated with an old ripe collodion, and sensitized in an old acid bath. The developer should be weak in iron, and strong in acid, both acetic and citric being used. With an excess of acetic acid a very warm tone can be obtained, but there is a loss of brilliancy; with excess of citric acid more brilliancy is obtained, but the tone is cold blue - black; in fact, a nice adjustment of the two is required to give just the proper amount of warmth without sacrificing brilliancy. It is mostly recommended to fix with hyposulphite, but I prefer to use cyanide, as it is so much easier to wash away, and any hyposulphite remaining in the print after transferring will, of course, cause fading. Do not develop fully, as you will find the development go on while washing. If albumen paper is to be used for transferring, it should be cut to the size of the plate, placed in a bath of methylated spirit for five minutes, laid upon the still wet collodion picture, and squeezed down. When dry, it will peel. If gelatinized paper is used, it must be soaked in warm water, and applied in the same manner. - George Crocouhton.

Iodizers for Transfer Collodion. -

1

Iodide of Ammonium,................

1 1/2 grains.

Iodide of cadmium,................

1 1/2 grains

Bromide of Ammonium,................

3/4 grains

Bromide of Cadmium ,................

3/4 "

Chloride of Ammonium,................

1 "

2.

Iodide of Ammonium,................

2 1/4 grains.

Bromide of Ammonium, ................

1 3/4 grains

Iodide of Potassium,................

3/4 grains

Bromide of Potasium.....

1/4 grains

Chloride of Ammonium................

3/4 "

3.

Iodide of Ammonium,................

1 3/4 grains.

Bromide of Ammonium,................

3/4 grains.

Iodide of Cadmium,................

3/4 grains.

Bromide of Ammonium,................

1/4 "

Chloride of Ammonium,................

1/4 grains

One ounce of the collodion should contain any of the above formulae. If the addition of . say, to thirty ounces of iodised collodion of No. 1 formula one drop of aqua regia be added, it will be found to answer admirably for opals. Methylated ether answers all requirements for this class of work, but it is much better to use alcohol than methylated alcohol, as many of the defects met with in the manipulation are mainly due to the injurious effects produced by methylated alcohol in the nitrate bath. Collodion. - Six grains of cotton to each ounce of ether and alcohol in the following two fers, but is better for the other work. Any good, rather old collodion will answer that will give fine details and not too violent contrasts. The plates must be carefully cleansed and prepared.

proportions: Two parts of alcohol and one part of ether in hot weather, and equal parts in cold weather.

The nitrate hath should not exceed twenty-five grains to the ounce of water, hut will work well down to fifteen grains, and should be rather acid with nitric acid. In working, the most troublesome defects are white spots, black spots, and white streaks. The first are caused by the bath being saturated with iodide, etc., and can be remedied by adding to the bath one-third of its fluid bulk of plain water, filtering, and strengthening again to bring it to its proper strength. The second are caused, sometimes, by the bath being too strong for the collodion, and may be reduced. If that does not answer, add a little plain collodion to the collodion in use, and should this fail, try one drop of nitric acid to every twenty ounces of iodized collodion, adding at the same time a drop or two more of nitric acid to the silver bath. One or other of the above will invariably answer. White streaks are, like the first, due to the same cause, and will often appear in a new bath. In this case, add a little more iodide to the bath, filter, and add slightly more nitric acid.