BLOCK Stop Bath
In conventional stop baths, the acid ingredient which stops development is hazardous, unpleasant to use and can damage prints.
Acid can break down print sizing which normally protects fibers from fixer thiosulfate contamination, a major cause of deterioration. Plain water stop baths eliminate the side-effects of acid, but do not stop development as effectively, and can cause stains, emulsion swelling and reticulation.
BLOCK is an acid solution, but the acids are buffered to minimize side-effects. Buffering protects print fibers for greater permanence, reduces emulsion swelling, staining, reticulation and eliminates odors. BLOCK will also prevent carbonate gas ruptures of films (pinholes) when used as directed.
BLOCK is the basic stop bath for all SPRINT™ SYSTEMS processes. Always use BLOCK Stop Bath before fixing with RECORD Alum Hardening Converter to provide the correct acid value.
One liter of BLOCK Stop Bath concentrate will make 10 liters of working solution, enough to process (600) 8×10 fiber prints or (900) 8×10 resin-coated prints or (600) rolls of 35mm, 36 exposure film.
How to Mix
Dilute BLOCK concentrate 1:9 with water to make the desired volume of working solution.
|100ml||BLOCK Stop Bath Concentrate|
|=||1000ml||BLOCK Stop Bath Working Solution|
Stop Bath Procedure
Use BLOCK Stop Bath working solution at the same temperature as the developer solution. Never subject film to sudden temperature changes in processing; reticulation, or an apparent increase in graininess may be the result.
For Films: Immerse for at least 1 Minute with continuous agitation.
For Prints: Immerse for at least 5 Seconds with continuous agitation.
Hardening Stop Bath
BLOCK Stop Bath may be converted into a hardening stop bath for sepia toning, or to replace hardening in the fixer if sulfur dioxide vapors must be minimized. Substitute the following converted working solution for the normal stop bath and immerse films or prints for 3-6 minutes with agitation.
|40ml||BLOCK Stop Bath Concentrate|
|60ml||ARCHIVE Fixer Remover Concentrate|
|+||30ml||RECORD Alum Hardening Converter Concentrate|
|=||1030ml||Hardening Stop Bath Working Solution|
When mixing hardening stop bath, the order of mixing is important. The Archive and Block concentrates may be mixed with water in any convenient order, but the Record Alum Hardener Concentrate must be added last.