Much like hydroquinone and metol. the only diference is that catechol is a tanning developer. Catechol formula is o-dihydroxybenzene and hydroquinone is p-dihydroxybenzene, as you can see the only diference is in the placement of the hydroxyl group, this might be significant in the superadditivity effect, but I suspect it is not. Without doing a complete mechanism study is hard to tell but it is my feeling that metol/catechol and metol/hydroquinone behave very similarly. It is one of the reasons I dont use metol in my formula, I think your stain will improve if you reduce the metol quantity, plus you will get a better "compensation" effect from the stain with less metol. The only draw back to reducing metol is the smaller EI. Ok, good luck with your formula.(posted 8456 days ago)