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As a negative and positive developer, amidol enjoys a certain popularity on account of its freedom from fog, good tonal reproduction and universal use, as well as its capacity for producing a deep velvety black on bromide papers.

Focal Amidol universal developer, stock solution
Ingredient Quantity
Mix chemicals in order.
Sodium sulphite, anhydrous 25 grams
Potassium bromide 1 gram
Water to make 1 liter
For use take 100 ml of stock solution and add:
Amidol 0.5 grams

Note: It is advisable to add the amidol to the stock solution just before the developer is to be used. Do not dilute.

Times for development:

  1. For plates and films: 3 – 5 minutes. The image appears quickly but the negative must be thoroughly developed, since the density tends to weaken in the fixing bath.
  2. For bromide papers: 1.5 – 2 minutes.
  3. For gaslight contact papers: 45 – 60 seconds.

A solution containing amidol does not keep more than 2 – 3 day; therefore, it is best to make up a stock solution as described, the amidol can then be added immediately before use and no more solution made up than is required at the moment.

Note: As amidol developer contains no sodium carbonate, it does not tend to soften the gelatine of the emusion; it is, therefore, suitable as a tropical developer.