Newton Ringsgreenspun.com : LUSENET : Large format photography : One Thread
I have a Durst enlarger that I use to blow up my negatives. I have taken off the glass from the tray because pushing on the film it gave on the print the Newton rings. After I cleaned very well the glass two o three times but it still gave me the same problem. Now I'm printing without it: for the small format I haven't problems, but for the medium format the negative bends itself going out of focus. I read about this on my Ansel Adams book "The Negative" but it dosen't give an exhaustive explanation. Please have anyone a good way to solve this trouble? Thanks
-- Gino PRINI (email@example.com), November 19, 1999
saunders makes universal negative carriers that use anti-newton glass.
-- jnorman (firstname.lastname@example.org), November 19, 1999.
Enlarger manufacturers, including Durst, offer AN glass carriers.
If you have too old an enlarger for current glass to fit you can order AN glass from Condit manufacturing in CT>
-- Bob Salomon (email@example.com), November 19, 1999.
Another good source of anti-Newton's ring glass for enlargers is Focal Point Industries at http://www.fpointinc.com/ , click on Focal Point Products.
-- Michael Briggs (MichaelBriggs@earthlink.net), November 19, 1999.
This is a particularly tough problem that I have worked on for years. I will tell you what I am currently doing. It works 97% of the time and is especially effective for fine grain films that have a particularly smooth emulsion side.
First you use anti-newton glass on the top half of you glass holder. Since the smooth polyester surface faces the anti-newton glass this such eliminate 90% of your problems. Films whose gelatin (emulsion) surface is exceptionally smooth will still give you newton rings. Solution? Have the bottom surface (glass) multi-coated. If you are using a 6*7 carrier this should not be a major problem. Just run down to you optical, yes the same people who makes your glasses, and they should be able to help you. If on the other hand you are using a 4*5 carrier then things get dicey to say the least. Try getting any optical to multi-coat a 4*5 piece of glass. They are just not setup to handle large pieces of glass. But where there is a will there is a way. Beattie interscreen will sell you a piece of multi-coated cover glass cut to your specifications. They will even square the edges for you! Ask to speak with John. He was a particularly helpful fellow. Check the thickness of the glass before you install it. I had to shims to bring it up to spec when I used it in my 4*5 Saunders glass carrier. It works great. You heard it here 1st.
-- Pat Raymore (Patrick.firstname.lastname@example.org), November 19, 1999.