D-85 paper developer

Description

A high-contrast hydroquinone developer on paraldehyde bisulphite, made for lithographic and line materials. Black and white with almost nothing in between.

What it gives you

Hydroquinone in alkali, with no metol or phenidone, works as a contrast amplifier: density builds avalanche-like and the mid-tones all but disappear. For copying line originals, text or drawings that is exactly right.

Where it belongs

Technical reproduction, photo masks, high-contrast experiments on paper. For ordinary exhibition printing the contrast is excessive — D-72 is the developer there.

Questions and answers

Why does the solution darken faster than usual?

Hydroquinone oxidises more readily in strong alkali. Keep it in a full, tightly closed bottle and do not leave it standing in the tray.