As a rule the photographer who follows the printed formula is the photographer who gets the best results. The development of Portrait or Commercial Film is very simple with either the tray or the tank method, but for convenience, economy and quality of results tank development is recommended.

The first users of films were big consumers and practically all of them used the tank method. The number of big consumers is constantly increasing, but smaller consumers are also being added to the list daily.

Many of these have made their beginning with tray development, and while tray development of films is more simple and convenient than tray development of plates, there is still greater convenience in tank development.

For either tray or tank development Pyro is recommended,experience having taught that the best results possible are produced by this developer. The peculiarity of Pyro, however, is that the color which gives the best printing quality in the negative is produced by a slight oxidation of the Pyro.

FROM AN EASTMAN COMMERCIAL ORTHO FILM NEGATIVE

General Electric Co. Schenectady, N. Y.

If the necessary chemicals are added to a Pyro developer to give it good keeping quality, oxidation is retarded and the Pyro color is more or less eliminated. The three following formulas have been worked out for film and found to give the most satisfactory results.

The first is recommended for the excellent printing quality of negatives it will produce, which more than makes up for the trouble of preparing fresh solution for each batch of films that is developed.

The second developer gives medium warm tones. It will keep for two days and give negatives of excellent quality, but it must be discarded after two days' use. This developer will be found a great convenience by those photographers who have a fair number of negatives to develop each day and prefer a slightly warm-toned negative. It gives Pyro quality but has the advantage of reasonably good keeping quality.

The third developer has excellent keeping qualities when compounded carefully in accordance with instructions, and by the addition of a strengthening solution will keep for several weeks and produce excellent results. The negatives are of a blue tone. The keeping quality, however, depends entirely on the proper compounding of the formula.

The three formulas are as follows:

A. B. C. PYRO TANK FORMULA FOR WARM TONES

For the one gallon tank take 5 1/2 ounces each of A, B and C and add water to make one gallon. For the 3 1/2 gallon tank take 19 1/4 ounces each of A, B and C, and add water to make 3 1/2 gallons. When large tanks are used, make up the large quantity of solution. Develop for about 12 minutes at a temperature of 65° F. Any scum that may form on the surface of the developer must be removed before developing films.

Tank Development Formula For Medium Warm Tones

FROM AN EASTMAN PORTRAIT FILM NEGATIVE

The B. F. Goodrich Rubber Co. Akron, Ohio

FROM AN EASTMAN COMMERCIAL ORTHO FILM NEGATIVE

The B. F. Goodrich Rubber Co. Akron, Ohio

FROM AN EASTMAN PORTRAIT FILM NEGATIVE

General Electric Co. Schenectady, N. Y.

The following instructions must be strictly followed, as the keeping qualities of this developer depend entirely upon the method of preparation.

Dissolve the Sulphite first, in three quarts of hot but not boiling water. When dissolved, add the Bisulphite and then boil the solution for five minutes. Cool to about 70° Fahr. and add the Pyro. Dissolve the Carbonate in one pint of warm water. Pour these two solutions into the tank and make up to one gallon with water, or three and a half gallons, as required. Develop for about 13 minutes at a temperature of 65° F.

This developer gives a medium warm tone and will keep well for two days. The color progresses with the age of the developer. Any scum on the surface must be removed before developing films. It must be discarded after two days.

Tank Development Formula For Blue Toned Negatives

The following Pyro-Soda formula, based upon the use of a neutral sulphite obtained by the combination of Sulphite of Soda and Sodium Bisulphite, gives excellent results:

The following instructions must be strictly followed, as the keeping qualities of this developer depend entirely upon the method of preparation.

Dissolve the Sulphite first, in three quarts of hot but not boiling water. When dissolved, add the Bisulphite and then boil the solution for five minutes. Cool to about 70° Fahr. and add the Pyro. Dissolve the Carbonate in one pint of warm water, then add the Iodide. Pour these two solutions into the tank and make up to one gallon or three and one-half gallons with water.

The most satisfactory temperature for developing is 65° Fahr. The so • lution should not be used below 60°.When the developer is first made and used, the developing time at 65° F. is about 18 minutes.

This made-up developing solution may be kept in the Developing Box, but when not in use, it should be covered to prevent evaporation and deterioration. A floating cover of wood made to fit inside the top of the box is recommended.

After the developer has been used for several batches of films, it will be necessary to strengthen it with the addition of each new bath. The strengthening solution is made by dissolving the chemicals named in the following formula and using exactly the same method for preparing it, as when preparing the first developer.

STRENGTHENING BATH FORMULA

Add this strengthener to the developing solution in the tank as needed, to keep up the developing strength of the solution.

Get the BEST result, use EASTMAN PROFESSIONAL FILM

FROM AN EASTMAN COMMERCIAL ORTHO FILM NEGATIVE

General Electric Co. Schenectady, N. Y.