Order online here or download a PDF version of these instructions here.


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 the 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 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.


BLOCK Stop Bath working solution changes color from yellow to lavender as it approaches exhaustion in B&W printing. When printing with QUICK SILVER Print Developer,
BLOCK Stop Bath and RECORD Speed Fixer mixed in equal volumes, BLOCK Stop Bath’s color indicator will signal the simultaneous exhaustion of all three solutions.


Dilute BLOCK concentrate 1:9 with water to make the desired volume of working solution.

100ml BLOCK Stop Bath Concentrate
+ 900ml Water
= 1000ml BLOCK Stop Bath Working Solution


Use BLOCK Stop Bath working solution at the same temperature as the developer solution unless otherwise directed in your processing instructions.

For Films: Immerse for at least 1 Minute with continuous agitation.
For Prints: Immerse for at least 5 Seconds with continuous agitation.


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
900ml Water
+ 30ml RECORD Alum Hardening Converter Concentrate
= 1030ml Hardening Stop Bath Working Solution

When mixing other quantities of hardening stop bath, please be sure to maintain the correct proportions and order of procedure described above.


One liter of BLOCK Stop Bath working solution will process at least (60) 8×10 fiber prints or (90) 8×10 resin-coated prints or the equivalent of (60) rolls of 35mm, 36 exposure film.


Stored as concentrate or working solution, with or without air in the container, BLOCK Stop Bath has a shelf life of at least 2 years.

BLOCK ® is a Registerd Trade Mark of Sprint™ Systems of Photography

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