Moersch ATS Acidic is a rapid ammonium thiosulphate fixer, 1 л concentrate, pH 6,0–6,5. Odourless.
What it is for
A general-purpose rapid fixer without hardener, for film and paper. For paper the maker recommends a two-bath sequence: 45 seconds in each at 1+5, which is more reliable than a single bath and extends capacity noticeably.
How to dilute it
The working dilution is від 1+5 до 1+10.
A litre of concentrate fixes 150 to 200 films. Fixing time at 1+5: film 2–4 minutes, paper 45–120 seconds.
The solution is replenishable — kept and reused, with development time extended as it exhausts. Keep count of the films put through it; that is the only way to avoid an underdeveloped roll at the end of its life.
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 difference between an alkaline and a slightly acid fixer is not a formality. The alkaline one is required if you develop in staining developers: acid destroys the pyro stain the developer was chosen for.
