F*$%!ng! newton rings on my contact prints?

[ic-racer]

This is how I do it for 8x10. I am using a glass (not a contact frame) and I start the exposure immediatly after the glass is lowered. The Newton rings move around a little before they settle in to a fixed pattern. So, if the exposure is in the 30 sec range the rings don't show up or are minimized considerably.

You should be able to see the rings by looking at the reflecton of the safelight on the film under the glass. Watch how they move around as you raise and lower the glass and you will see what I am talking about.

[sanking]

Best solution is to just replace the glass with the anti-flare glass available in framing shops as others have mentioned. There is no down side to this and it is a permanent solution that is 100% effective.

Sandy King

[wildbill]

I printed a few other negs and couldn't see any rings although those negs didn't have empty areas of even tone either. I'll replace the glass with the anti glare stuff. thanks everybody

[bill@lapetelabs.com]

HI wildbill,
Try Anti-Newton glass, I find that fpointinc.com is a good source. We buy our replacement glass for our Durst 184 glass negative carrier from them and they will cut and sand the edges to fit your needs.

[Andrew O'Neill]

Up until now I've been doing my 8x10 contact prints with just a hinged piece of glass. No problems.

Send the new one back for a refund, and go back to your old one.

[EASmithV]

As said before the ANR glass should help, but also try sliding a thin piece of board or thick paper in the edge to lift the glass up ever so slightly off the film.

[RJS]

So you went and bought the more expensive, purpose made one and fixed what wasn't broken! Welcome!

[EASmithV]

Best solution is to just replace the glass with the anti-flare glass available in framing shops as others have mentioned. There is no down side to this and it is a permanent solution that is 100% effective.

Sandy King

Wait, anti-flare glass totally eliminates newton ring problems? I know this seems like a dumb question, but I need to know before I go off and buy 20 lbs of the stuff lol.

[Nicholas Lindan]

There are two types of 'anti-flare/glare' glass sold by framing shops: one is coated with an anti-reflection coating just like a lens; the other is very lightly frosted and a bit like a soft-focus filter.

Either one will eliminate Newton's rings: the anti-reflection coating will reduce them because it won't reflect light back from the film surface and so there is much less constructive/destructive inteference; the lightly frosted glass will break them up because the distance from the glass to the film is always changing rapidly - for light a change in distance of 500 nanometers is considered monstrous. You only need the treatment/coating on the side that presses against the negative.

Another possibility that just came to mind, and I haven't tried it so caveat emptor and all that, is frosted Mylar. It comes frosted on both sides and if placed between the negative and the glass should completely eliminate the rings. The frosting is exceedingly fine and won't show as texture on the final print. A blueprint shop or art supply house should have/get some, an 11x17 sheet should cost no more than a few dollars.

[Captain_joe6]

I've been using a regular old sheet of 8x10 glass in an ancient springback frame, and the strange part is, when I'm printing in my home darkroom i get no rings, but when I travel across town and print the exact same negatives, I get rings all over.