Quote Originally Posted by Sal Santamaura View Post
...newton rings are almost impossible to avoid in glass carriers. Delta 100 sheet film's emulsion side's glossiness falls between those two, but is much closer to TMY-2's. I've never managed to get a Newton's ring with Delta 100 sheet film. Extreme high humidity ambient conditions might be sufficient to cause them, however.
Quote Originally Posted by interneg View Post
Interesting - I've had a hell of a time trying to get rid of Newton rings on a Kodak pin registered contact print frame with both Delta & HP5+ - to the point that getting an AN glass for it seems the only solution - and room humidity isn't higher than about 55%.
Please note that my post referred to film's emulsion side contacting bottom glass in a negative carrier. With contact printing, your rings are coming from the film's base side touching frame glass. Every sheet film I'm aware of does that (except 320TXP, which has a dull base-side retouching coating) and almost demands anti-Newton glass when contact printing. This also applies to a glass negative carrier's top glass. All of my enlarger glass carriers are configured with plain bottom and anti-Newton top glasses.