328. Prepare Your Developer As Follows: - Stock Solution, No. 1

Water......................................

6 ounces

Sulphuric Acid,C.P

. 1/2 dram

Pyro.......................................

1 ounce

Note. - If softer results are desired use water twelve ounces in place of six, the other stock solutions remaining as they are, as the object is to change the strength of the pyro only.

Mix these chemicals in the order given. Add the acid gradually to the water. Never add the water to the sulphuric acid. By adding the pyro last you avoid early discoloration of this stock solution.

329. The sulphuric acid, used in Stock Solution No. 1, will preserve the solution from discoloring, and it also has a tendency to retard the development, and will hold the shadows clear and free from fog - sulphuric acid contains a fraction over ninety-two per cent, pure acid and, therefore, must not be used in excess quantities. Nitric acid may be substituted, if one so desires, but as the latter contains only sixty-eight per cent, pure acid, one dram should be used in place of a half dram of the sulphuric. As nitric acid has less retarding qualities (being a weaker acid), it is recommended for slow developers. As this formula is for a rapid developer, we recommend sulphuric acid.

Stock Solution No. 2

330. Procure a thirty-six-ounce bottle. Into this pour two ounces of Solution No. 1, and add thirty-two ounces of water.

Stock Solution No. 3

Sulphite of Soda, 40 hydrometer test, or by weight,

Sulphite of Soda (anhydrous)............

1 ounce

Water....................................

13 ounces

Stock Solution No. 4

Carbonate of Soda, 20 Hydrometer test, or if by weight,

Carbonate of Soda (anhydrous) ...........

1 ounce

Water................................................................

23 ounces

If soda crystals are used you will require double the weight.

331. Use only the very best of chemicals. We would recommend anhydrous sodas C. P., and advise hydrometer test in preference to weight. Prepare all stock solutions in the order given.