Developer. -

Pyrogallic Acid,.....................

3 grains.

Citric Acid,..................

6 "

Water,..................

1 ounce.

Methylated spirits to requirement.

The above is for hot weather.

Pyrogallic Acid,..................

3 grains.

Citric Acid,..................

2 "

Water,..................

1 ounce.

Methylated spirits as required.

This is for cold weather. Use Schering's pyro. The best results have been obtained by taking one ounce of pyro, dissolving it in boiling water, and adding the necessary citric acid to it, using this as a stock solution in the same proportions as above.

Development, although so simple, is probably the cause of many failures or objectionable results which are too often attributed to other causes. In very few processes can so great a latitude of over-exposure be kept under during development as in this. Take an ordinary square block of wood, nail a piece of thick leather at each corner, and the block can be levelled by the use of a few wooden wedges placed as wanted. If the plate exposed be placed upon this and is perfectly level, take care, in flowing on the developing fluid, not to wash off the free silver; or, in other words, to spill the developer from off the plate. The solution is left on the plate, and if it has been properly exposed, the image, after one or two minutes, will gradually appear if the negative was thin and weak. As soon as all the image has been perceived faintly, then proceed as follows: Pour off all the developer, and rock the plate to and fro. This will give a brilliant, strong, and clean image; whereas, if the whole liquid had been retained, the resulting effect would resemble the negative - that is, weak and flat; but should the negative be one in every respect suitable for enlarging, it is only necessary to watch the plate on the block and cut off a little sooner than the requisite force has arrived, as with the greatest rapidity of washing the developing action goes on slightly after the water is on. Great paint should be taken to be sure that no trace of the pyro is left on the surface before fixing, otherwise, the hyposulphite solution is rapidly discolored, and, of course, the plates fixed in a discolored solution cannot remain so clear and bright as in a perfectly fresh fixing bath.

865. After the enlarged positive is made it is, as has been already stated, transferred to paper, or it may be some other substances, such as glass, wood, porcelain, metal, or fabrics. This operation is a very easy one, and resembles that described for making the glace prints in Lesson 8. Of course there is room here, too, for care and thought, and fail will occur until some experience is had.

Fixing Solution. - Use rather strong hyposulphite of soda. After fixing, it is again very necessary to wash well, and it is advisable, even after a very prolonged washing, to take the following precaution: In a weak solution of permanganate of potash immerse the plate, allow it to remain a few minutes, and then wash well afterwards. - X. Y. Z.

Any bath and collodion that works clear in the shadows will do; the collodion should be old, and the bath quite acid; the bath must be as weak as it will work with the collodion - we get the best results at about twenty-five grains. The developer must be pyro; a good one is as follows:

Water,..................

1 ounce.

Pyrogallic Acid,..................

5 grains.

Citric Acid,..................

3 "

Acetic Acid,..................

1/2 drachm.

Alcohol if necessary to make flow smooth. The positive should be timed so as to develop quite slowly; do not develop too far, or the whites will not be clear. It is not necessary to wash after developing; place in hypo and let it fix; but I wash a little, so as to keep in the habit, as, in using the iron developer, they must be washed; after fixing, they must be well washed, but be careful, or the film will loosen, the plate not being albumenized. To prepare the plate, polish with alcohol and water, then rub with a solution of wax, five grains; benzole, one ounce; this is necessary to enable you to strip the film off after it is dry. - J. H. Folsom.

866. After your transparency is fixed and well washed, your gelatinized paper (which, in the meantime, has been soaking in cold water a few minutes) is laid carefully on the collodion film, the water and air are squeezed out with a squeegee, not pressing too hard, the surplus edge of paper is cut off, and the whole left to dry, when, by cutting along the edge, a thin knife may be inserted under the corner, and the film stripped from the glass. To gelatinize the paper, dissolve by heat two ounces of gelatin to a quart of water; keep hot, and float the paper about three minutes and hang up to dry, when it is ready for use. Heavy Saxe plain paper will do, but there is a cheaper paper which is as good, or better, for this purpose, which you can get at any paper warehouse; the paper must be gelatined in cold weather or in the evening, or it will run; a large quantity can be prepared, as it will keep. - J. II. Folsom.

Gelatin Transfer Paper. - Plain Saxe or Rives floated on a solution of ordinary gelatin:

Gelatin,..................

10 ounces.

Water,..................

1 gallon.

Chrome-Alum,..................

1/2 ounce.

Float a minute and a half, and hang up in a room of any temperature not lower than 65

366. The coloring upon the collodion transfer must be rapidly done, since the price at which they are sold in the market is extremely low. They are usually done in oil, and certainly he or she or it who colors them must be an illy-paid expert. The finest results are obtained by the use of crayon or India - ink, and when that is used the matter is not so difficult.

This will keep two months, or even for any length of time, by slightly increasing the amount of chrome-alum. To make it become attached to the plate it requires simply to be floated, face downwards, in water a short time previous to use, and squeegeed on as usual. The glasses for use can be cleaned in any way preferred, and then dusted on with talc, and the talc polished with a nice, clean, and thoroughly-dry leather. If the leather be damp, do not expect the paper to peel off the plate. Should, after all has been completed, the picture refuse to peel off the glass, add a few drops of glacial acetic acid to some water, and steep the back of the paper with this; it will readily peel afterwards. In hot weather it is often a good precaution to add one or two drops of glacial acetic acid to every pint of collodion; this is the best remedy against sticking. - X. Y. Z.