Roger is quite correct. Interference is happening all the time, even with anti-newton-ring (ANR) glass. Low humidity is another possible answer to your problem. The lower the humidity, the less problems you will experience with Newton's Rings. Even if you are also using ANR glass. I have a room dehumidifier in my darkroom and in my digital lab area. I prefer not to use ANR glass because I can sometimes see the pattern etched into the surface of the ANR glass on my enlargements, scans, and contact prints. The amount that I notice it seems to depend on the type of image -- it's worse in areas of almost even tonality such as clear, blue sky. Sometimes I can't get rid of the rings without using ANR glass, though. I wouldn't recommend using ANR sprays or powders. (I'm paranoid about putting anything like that on my film.) If you do choose to go that route, use it very sparingly. Less sometimes works better than more. Tetenal makes an ANR spray that I have tried and used successfully.
--Bill Nowlin ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Friday, October 19, 2001 10:49 AM Subject: Re: filmscanners: Glass slide mounts It's "interference," not difraction. The surface of any transparent ojbect reflects at least some of the light and that light then adds to or subtracts from the wave front traveling towards it. Depending on the distance (as measured in wavelength of light) between the two surfaces, the light at a given point becomes brighter or darker. An anti-newton surface is simple a rough surface that doesn't reflect light as uniformly as a very flat surface, so you don't notice the dark and light rings. But the reflections and interference is still going on and has the result of reducing the contrast of the image ever so slightly. The same thing happens in multi-element camera lenses where reflections from each glass surface unavoidably reduce the contrast of the lens. If you don't want to mess with glass anti-newton slide mounts, you might consider upgrading your Nikon to a Polaroid. (On that issue, I agree with Art and his comment that Nikons have more of a focus problem due to! their weak light source and there fore require corrective measures with curved film, such as using glass mounts.)