The following is from one of the Kodak publications the very good J series.
This formula is D-23 with sodium bisulfite added to lower the pH of the developer. This supresses the action of the Metol thereby increasing the time necessary to produce the same gamma as D-23. This modification produces finer grain since the sulfite has a longer time to work. Kodak in Publication J-1 describes D-25 as producing grain comparable to paraphenylenediamine developers. See page 35.
http://www.bonavolta.ch/hobby/files/Kodak j-1.pdf
At one time Kodak sold benzotriazole as small tablets. The bottle described adding one or two tablets per quart to high sulfite developers like D-23 or D-76 to produce finer grain. Same principle the antifog suppressed the developer allowing the sulfite to dissolve more silver halide.
This formula is D-23 with sodium bisulfite added to lower the pH of the developer. This supresses the action of the Metol thereby increasing the time necessary to produce the same gamma as D-23. This modification produces finer grain since the sulfite has a longer time to work. Kodak in Publication J-1 describes D-25 as producing grain comparable to paraphenylenediamine developers. See page 35.
http://www.bonavolta.ch/hobby/files/Kodak j-1.pdf
At one time Kodak sold benzotriazole as small tablets. The bottle described adding one or two tablets per quart to high sulfite developers like D-23 or D-76 to produce finer grain. Same principle the antifog suppressed the developer allowing the sulfite to dissolve more silver halide.
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