Robert I have seen a number of references to this substitution, but can only find one example at present: http://unblinkingeye.com/Articles/LithDev/lithdev.html See the note under the D-85 formula. I have no idea whether it works! Don Sweet ----- Original Message ----- From: Robert Hall To: pure-silver@xxxxxxxxxxxxx Sent: Monday, March 01, 2010 1:34 PM Subject: [pure-silver] Paraformaldehyde/Acetone in lith developers Fellow Silverados... Does anyone know what the purpose of Paraformaldehyde is in lith developers? If Acetone can be substituted, what is the ration of the substitution? How does Acetone compare to Paraformaldehyde in the resulting print? Thank you in advance. Robert Hall www.RobertHall.com