Sprint Systems of Photography Block Stop Bath for Black & White Film and Paper - 4 Liters

Sprint Block Stop Bath is a buffered, vanilla scented stop, which Safely and effectively stops development and adjusts the ph of b&w films and prints without unpleasant side-effects.

An indicator color signals exhaustion in b&w printing solutions. This stop dilutes in a 1-9 ratio.

Using Block: In conventional stop baths, the acid ingredient which stops development is hazardous and 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 and 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.