Rollei RHC High Contrast is a high-contrast liquid concentrate, 1 litre, for technical, micro and repro films as well as for paper.
What it is for
A developer for when contrast needs raising rather than taming: line-art reproduction, microfilm, technical work. On paper it lifts contrast by roughly one grade — which hands a tool to anyone working with fixed-grade paper who otherwise has none. It is especially useful as the soft half of a two-bath printing pair.
How to dilute it
The working dilution is 1+4.
It is a one-shot developer: mix the working solution, use it, discard it. That is the most predictable way to work — every film is developed in fresh solution, so times need no extending from roll to roll.
Storage
Sealed concentrate keeps well but dislikes air: the emptier the bottle, the faster it oxidises. Decant the remainder into a smaller bottle, or displace the air — that is what gets a concentrate to its last measure.
How it compares
The mirror image of Rollei RLC in this same catalogue: that one softens a technical film, this one sharpens an ordinary one. Together they cover both ends of the range.
