Go for the AN glass; it works perfectly, you avoid the Newton rings and you don't do any damage to the negative. As Michiel said, you only need it on the top. No downside except the two additional surfaces to keep clean; but you'd have those whether you used AN or regular glass. Bob Younger -----Original Message----- From: pure-silver-bounce@xxxxxxxxxxxxx [mailto:pure-silver-bounce@xxxxxxxxxxxxx] On Behalf Of john stockdale Can anyone tell me if the AN glass is needed and if there is any downside to using it? John Stockdale ============================================================================================================= To unsubscribe from this list, go to www.freelists.org and logon to your account (the same e-mail address and password you set-up when you subscribed,) and unsubscribe from there.