It's odd, how these things behave. There have been so many reports of contributing factors and remedies that it's really hard to find the common thread. Loose Gravel's report that diffuse light sources diminish the NR effects is directly opposite my own. I'm sure LG's report is factual, but I HAD to use use a diffuse source to see the problem with Kevin's frame. When I first tried to see the rings, I tried sunlight. All I could see were a few small patterns (even with a magnifying glass). I tried incandescent light, but still no results. When I got the little light box I use to view slides (very diffuse), and looked at the reflection of it in the printing frame the NR's were everywhere, and very well defined. Could be the difference is transmission vs reflection. Anyway I'm glad to hear that menglert's problem is fixed.
I'm nowhere near a pro contact printer, but I've done about 40 the last 2 days (small ones, 8x10 max) using a contact printer (paterson) and also a "sandwich" with 2 plain plates of "opticaly perfect" glass.
The first handful of prints I could see newton ring patterns in the glass (both mounts), at an angle.. Since I was testing exposure etc, I ignored them and I kept at it without cleaning the glass (apart from obvious marks) and after 10 prints or so the rings disappeared completely.
So maybe having a "worked out" piece of glass makes a difference ? It could amount to a residue of dust etc from the various negs that were pressed against the glass, but it made a fantastic difference...
I think that now I will "train" the glass a bit before important prints...
To add to this thread:
I live in Utah. Very dry. I get NR if I lay the negative on the glass right after cleaning. If I let it dry, they go away.
I also use a single side anti reflection glass for silver printing. I would like to use it for platinum as well, but it is also a 94%uv glass. It tends to slow things down a little.
I hope to find a source of non-UV antiglare glass. Anyone? Anyone?
I get the best result with AN glass. I have tried Denglas which is recommended by Ctein..not very effective for me.
For 6x7 and smaller negatives one may buy AN slide mounts in 85mm square.
You will get 20 pieces on AN glass and 20 pieces of regular glass.
One method that I have found to be effective with regular glass is to tape the long top edge to either an open frame or bottm glass and then apply tape to the opposite side and trim it to the negative width w/o overhang. Then I Tape a piece of regular glass over this. The glass pushes the film flat and since the glass is resting on the tape the newton rings go away. This is fairly effective. Sometimes I still need to use AN glass. As far as the Denglass I do not recommend it.
Originally Posted by Claire Senft
Just an interesting aside, Denglass went out of business in April of this year.
I too was having problems with Newton's Rings. I started using a piece of frosted glass on the top side of the neg carrier. It works great, except for when i try to print overexposed film. That stuff comes out looking really grainy. Anyone else have this experience? Is it fixable?
Howard Bond related that he used a glass holder on his 8x10 enlarger and never experienced any Newton rings. While photographing the Cathedrals of England, he stood on Isaac Newton's burial spot in Westminster Abbey..when he returned home and began to print, there were Newton rings!!...EC
There is a glass that seems to be slightly frosted and used for framing. You can find it at Joann Fabrics, Michaels, or I'm sure other framing shops. I forget the exact name of the glass, but ask to see samples of their selection and you can easily pick it out. It has a very faint and fine frosting to it.
That's the glass, I was talking about. It's the anti-glare picture framing glass. It should work above the negative.
Originally Posted by menglert
you also get it at halbe.de .