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Presentation solutions: phenidone
PHENIDONE DEVELOPER

Alvididone is a new reducing agent from Ilford Factories research that can be used in show solutions alongside hydroquinone. If used alone, it would lead to a very low degree of contrast, but it works to shorten the induction period to a very large extent. The “induction period” is the time that passes from the moment the film is dipped in the display solution until the first signs of blackness begin to appear in the latent image. The induction period is almost zero when fenidone is used. The speed of manifestation when combining phenidone and hydroquinone exceeds its speed when using methol and hydroquinone (assuming that the pH value is the same in both cases), and the manifestation = with phenidone remains active even if the pH decreases.

Experiments confirm that fenidone leads to fog when showing sensitive films, but this problem can be overcome if an amount of benzotriazole equal to 15 grams per liter is added to the presenting solution.

In the preparation of show solutions with phenidone and hydroquinone, the hydroquinone is dissolved before the phenidone, which is pre-mixed with some potassium metabisulfite salt Pot. Metabisulphite is 2.5 times the weight of phenidone.

Experiments did not prove that phenidone salt has an effect in provoking skin infections for some people, as is known about methiol. We show, in the following, an example of the composition of a show solution with fenidone.