674. Example

Example. Highlights appeared in 24 seconds and the plate was taken out 240 seconds after the developer was poured on. The print from this negative showed proper contrast.

240 seconds total development. 24 seconds highlight appeared. 10 factor for developer.

For future development with a watch or metronome, note the number of seconds elapsed between the pouring on of the developer and the appearing of the first highlight.

675. Example

Example. Highlights, 35 seconds; time, 10-350 seconds. Cover tray to protect from the developing light and continue rocking. Three hundred and fifty seconds after the start take the plate from the developer, rinse and fix.

Different developers have different factors. We suggest the following factors for use with our own developing formula:

676. To use this system successfully, always use a normal developer.

For stronger negatives than the normal factor gives, use a higher factor. For weaker negatives use a lower factor. If the lighting is too uniform, flat prints will result and longer development will not improve the contrasts.

677. Temperature of the developer is an important condition in using the factor system. It should be kept uniform during development. Seventy degrees is normal for a developer. Cold developer works too slow and warm developer too fast. With a temperature of about eighty degrees there is danger of frilling.

678. Developers For Use With Seeds Plates.

Pyro.

679. In very cold dark rooms use five ounces of water. In hot weather use ten ounces of water. For double coated plates use eighteen ounces of water.

One-half ounce of B will give a warmer tone to the negative. The best printers have a warm brownish black color. If negatives are too yellow or the shadows show the slightest stain, not due to discolored fixing bath, use one and one-half ounce of B.

680. Sulphite of soda in solution does not keep well. Solutions over one month old should not be expected to be full strength if not made with pure water, and kept in well stoppered bottles.

681.

Eikonogen - Hydroquinone.

Factor 12.

For double coated plates add four ounces of pure water. Use more water in hot weather.

* If more concentrated developer is desired in order to secure more contrast, the water in solution A may be reduced to 32 ounces. Use boiling water in making up this developer. In cold weather a little glycerine could also be added to prevent precipitation.

682.

Metol - Hydroquinone.

Factor 15.

* Dissolve in the order given. Metol should always be dissolved in water before the sulphite is added, or before it is mixed with sulphite solution, otherwise it may precipitate. If crystal sodas are used add 15 grains of bromide of potassium to 16 ounces of B solution.

683.

Ortol.

Use equal parts of A and B.

Factor ii.

684.

Pyro - Metol.

685.

Plain Fixing Bath.

Do not use a discolored bath. Plates should be left in Fixing Bath at least double the time it takes whiteness to disappear. This bath must be made fresh every day.

686.

Acid-Fixing Bath.

687. See that chemicals are entirely dissolved, then pour B into A slowly while stirring A rapidly. This bath remains clear and fixes clean after long continued use, but should be replaced as soon as it becomes exhausted. Never attempt to restore a spent bath by adding more hypo. Plates should be left in bath at least double the time it takes whiteness to disappear.

688. If negatives remain twenty to thirty minutes in this bath, the film will become much hardened. This is a great advantage in summer when washing often softens the film. In hot weather fresh fixing baths should be made up more frequently. By fixing longer, less washing will suffice; fifteen minutes in running water is enough if plates have been thirty minutes in a fresh, quick working fixing bath.

The ounce avoirdupois (437 1/2 grains) is the one used.

The quantities given in formulae are mostly divisible by four, if smaller quantities of developer are desired. The following approximate metric equivalents may be used: