Developing Digital Photography Films

There is no better criteria to get to know the characteristics of a developer than experience. Commercial developers are made of different chemical agents that influence in the above characteristics. The energetic compounds develop density and contrast, and the week agents limit the size of the grain. Naturally, each type of film is more advisable for a type of developer, but the ultimate decision, which depends on the tastes and needs of the photographer, is very subjective. It is advisable to test various developers with each type of film and observe the results. Although, to an untrained eye, a developed negative is no different than any other except for the theme, the photographer can appreciate the differences of different developers.

Dissolution and Useful Life

The developer is perishable, it has a limited useful life. While chemical compounds in dust form practically don't have an expiration date, once they are diluted they have a tendency to rust. Generally, the instructions on powder developer allow us to obtain a concentrated solution (most developers are directly commercialized in this form). From here on, there are usually different option of use:

•  Working solution with recovery: Part of the concentrated solution is diluted in water, is used and then recuperated after developing as many times as the manufacturer indicates. With this system a compensation is necessary because of the developer wearing out, through an increase in developing time after a determined number of rolls.

•  Working solution without recovery (use and throw away): In this mode the concentrated solution is diluted even more and is used only once. As long as you are working with a fresh developer, which allows constant results. The concentrated solution deteriorates very slowly, and the one which is not recovered is prepared moments before use. On the other and, the solution that is recovered, which deteriorates quickly can be stored for a long time before it's new use.

Fixing

After developing, in the emulsion a silver image appear surrounded by unexposed and undeveloped silver halides, which are still sensitive to light. To avoid these compounds reacting to the light, meaning, to give the silver image stability, it's necessary to eliminate the silver salts present in the emulsion after developing. The fixer decomposes and makes the remaining silver halides water soluble and leaves a stable silver image on a transparent base.