Thanks for the feedback, Simon.
I use various countermeasures when the dreaded rings occasionally appear (everything from high quality anti-newton ring glass and/or coated glasses to TXP spacers). Sometimes simply wiping down the glass with alcohol works. It's an intermittent problem.
Thanks again. I was just curious about the statement in the article.
I have no idea.
Originally Posted by cmacd123
Based On Simon's reply I wonder where Howard Bond got his information or has he simply seen something on the surface of Ilford films that he believes will prevent Newton's Rings?
Did he qualify his statement in any way with potential elements of doubt as it sounds quite unequivocal to me as quoted.
To state a personal conclusion based on what you see and how you think that will decrease the incidence of Newton's Rings is one thing but stated as it apparently was seems to give his conclusion more foundation that it appears to deserve, based on Ilford's stated position .
In the article he doesn't say any more on the subject. I was going to contact him about it.
I'm curious if you could elaborate on the qualities or brands of 'ultra high quality' versus high or ordinary quality AN glass. Aside from trial and error, can you point us in the right direction?
Originally Posted by Simon R Galley
The improved scanning "tooth" on Kodak color films (esp sheet films) does in fact do an excellent job suppressing Newton rings, but not completely if you happen to live in a foggy climate like I do. Films like HP5, FP4, and TMY400 also are good in this respect. But there are a number of downright slick films out there, in which case I find it necessary to use antinewton glass on BOTH sides of the neg. The trick is to
have a very precisely adjusted enlarging setup, and use only as small an f-stop on the enlarging lens as necessary, to keep the depth of field
limited to the emulsion itself. Once you get beyond this basic comment, things get more complicated and require practical testing.
Paul - you won't find much in antinewton glass these days except from Focal Point. It's decent stuff, but maybe not equal to true Durst or Omega glass, if you can still find it, which have more of a wave rather than stippled pattern. Which kind of glass is best depends on the film,
the focal-length/angle and MTF of the enlarging lenses, f/stop and degree of magnification, the diffusion of the light source, etc,etc. I once had samples on hand of well over a dozen brands of antinewton glass from all over the world. Now all but one are out of production. Sometimes optically coated picture glass will do, but not in my climate.