X-TOL film developer

Description

An ascorbate developer built on ascorbic acid and phenidone — no metol, no hydroquinone. Grain as fine as D-76 with a small gain in film speed rather than a loss, and the lowest toxicity of the classic developers.

What ascorbate buys you

Ascorbic acid reduces silver as effectively as hydroquinone, and paired with phenidone the two are superadditive — the combination gives more than either alone. In practice that means shooting film at box speed, or a third of a stop above it, while keeping grain at D-76 level. That combination is rare: fine grain is usually paid for in speed.

Worth knowing

Ascorbate developers are more sensitive to water quality and to very dilute working states — the standard advice is not to go below 1+1 and not to keep a working solution in a half-empty bottle. The 10 L dry powder is packed component by component, so mixing a part-batch needs scales accurate to 0.1 g.

Questions and answers

How is it better than D-76?

Lower toxicity and a small speed gain at the same grain. Worse: it is fussier about water and about how a diluted solution is stored.

Why is the powder cheaper than the solution?

You are paying for reagents rather than for water and bottles. In exchange you weigh and dissolve it yourself.