Part 344

Water 10 ounces Metol 7 grains Sodium sulphite, crystals, pure 1⁠/⁠2 ounce Hydroquinone 30 grains Sodium carbonate, dessicated (or 400 grains of crystallized carbonate). 200 grains Ten per cent bromide of potassium solution, about 10 drops

«Amidol Formula.»—

Water 4 ounces Sodium sulphite, crystals, pure 200 grains Amidol, about 20 grains Ten per cent bromide of potassium solution, about 5 drops

If the blacks are greenish, add more amidol; if whites are grayish, add more bromide of potassium.

«Hypo-Acid Fixing Bath.»—

Hypo 16 ounces Water 64 ounces

Then add the following hardening solution:

Water 5 ounces Sodium sulphite, crystals 1⁠/⁠2 ounce Commercial acetic acid (containing 25 per cent pure acid) 3 ounces Powdered alum 1⁠/⁠2 ounce

«Amidol Developer.»—

Amidol 2 grains Sodium sulphite 30 grains Potassium bromide 1 grain Water 1 ounce

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With a fairly correct exposure this will be found to produce prints of a rich black tone, and of good quality. The whole secret of successful bromide printing lies in correctness of exposure. It is generally taken for granted that any poor, flat negative is good enough to yield a bromide print, but this is not so. A negative of good printing quality on printing-out paper will also yield a good print on bromide paper, but considerable care and skill are necessary to obtain a good result from a poor negative. The above developer will not keep in solution, and should be freshly prepared as required. The same formula will also be found useful for the development of lantern plates, but will only yield black-toned slides.

«PLATINUM PAPERS:»

«General Instructions.»—To secure the most brilliant results the sensitized paper, before, during, and after its exposure to light, must be kept as dry as possible.

The paper is exposed to daylight, in the printing frame, for about one-third of the time necessary for ordinary silver paper.

The print is then immersed in the developer for about 30 seconds, then cleared in 3 acid baths containing 1 part of muriatic acid C. P. to 60 parts of water, washed for a short time in running water, the whole operation of printing, clearing, and washing being complete in about half an hour.

As a general rule all parts of the picture except the highest lights should be visible when the exposure is complete.

When examining the prints in the printing frames, care should be taken not to expose them unduly to light; for the degradation of the whites of the paper due to slight action of light is not visible until after development.

«Ansco Platinum Paper.»—Print until a trace of the detail desired is slightly visible in the high lights.

Development.—Best results are obtained with the temperature of the developer from 60° to 80° F. Immerse the print in the developer with a quick sweeping motion to prevent air bells. Develop in artificial or weak daylight. The development of a print from a normal negative will require 40 seconds or more.

Formula for Developer.—

Water 50 ounces Neutral oxalate of potash 8 ounces Potassium phosphate (monobasic) 1 ounce

Care must be used to obtain the monobasic potassium phosphate.

Immediately after prints are developed, place them face down in the first acid bath, composed of

Muriatic acid, C. P. 1 ounce Water 60 ounces

After remaining in this bath for a period of about 5 minutes, transfer to the second acid bath of the same strength. The prints should pass through at least 3 and preferably 4 acid baths, to remove all traces of iron that may remain in the pores of the paper.

When thoroughly cleared, the print should be washed from 10 to 20 minutes in running water. If running water is not available, several changes of water in the tray will be necessary.

«“Water Tone” Platinum Paper.»—“Water tone” platinum paper is very easily affected by moisture; it will, therefore, be noticed when printing in warm, damp weather that the print will show quite a tendency to print out black in the deep shadows. This must not be taken into consideration, as the same amount of exposure is necessary as in dry days.