Substitute Ascorbic acid for bisulfite in Pyrocat HD

[Jim Noel]

I know that I read a post indicating that the substituting of either ascorbic acid or citric acid for bisulfite in Pyrocat HD works , but I can not find the post. does anyone have experience with this?

Thanks,
Jim

[sanking]

I know that I read a post indicating that the substituting of either ascorbic acid or citric acid for bisulfite in Pyrocat HD works , but I can not find the post. does anyone have experience with this?

Thanks,
Jim

I never tried to substitute citric acid for metabisulfite, but in terms of working characteristics only you can substitute about 4 parts of ascorbic for every 10 parts of metabisulfite. I recommend the metabisulfite for keeping qualities in the water based Stock A, but the ascorbic acid makes sense for the glycol based Stock A.

In either case an excess of about 2X either metabisulfite or ascorbic will kill the stain.

Sandy