"Newton's Rings" from Contact Printing?

[John Greenler]

I have recently started contact printing 8 x 10 negatives. I am quite pleased w ith my initial results except for a subtle but disturbing series of irregular co ncentric rings, which appear in print areas with even tonalities (such as clear skies). These rings are different on each print of the same negative. The nega tive itself looks fine when viewed on a light table. Correspondingly, the glass (in a frame) I am using is very clean. To fill in the details, let me also men tion that I am currently printing on Kodak Polymax II RC paper, glossy surface.

I have a suspicion that I am dealing with "Newton9s Ring9s", which I have read a bout as being a problem with glass negative carriers for large format enlargers. It strikes me that this effect could be coming from the glass-negative interfa ce, or the negative-glossy RC paper interface. Has anyone had this type of prob lem, and/or know of potential solutions? Has anyone had experience with "Anti-N ewton Spray" (Tetenal) to solve this problem? Could the glossy RC paper be the culprit? I was hoping that I could use this paper for the "proofing stage" of m y work, and then switch to fiber-base silver-gelatin paper for my final work.

Thanks in advance for any help or suggestions.

John

[Peter Hughes]

Sounds like the glossy RC paper is the culprit. But if the rings persist, even with regular FB paper, try several different peices of glass. You may find one that won't give you the rings. Also, there is such a thing as anti-newton ring powder. (I belive its powdered glass!) A TINY amount sprinkled on the neg will prevent newton rings. As far as where to get it, however, well, you might try a large graphic arts or printing supply house. Finally, I BELIEVE you can get anti-newton ring glass from Zone VI. Check them out.

[Sean Billy Bob Boy yates]

FWIW, I have had similar problems, but not with AZO, my current paper. It only comes in glossy, but of course is not nearly as glossy as an RC paper. When I did a quick & dirty print for a friend, on an Ilford pearl finish paper, I believe, WHAMMO! I got 'em. You could try Steve Shuart in PA, he advertises regularly in Shutterbug and sells anti-newton glass.

[Shigehiro Ishii]

Dear John and contributers,

I have same problem as you have even with FB papers but not with AZO like Sean. I think it has got to do with humidity and glass thickness. And uneven pressure between glass and paper generates Newton Rings. This is only secondhand information, but 2mm glass will solve this problem. I use Anti-newton powder called "Altas Powder" made in Japan and could REDUCE Newton Rings. I don't want to spend on expensive glassless vacuum frame so I use a pressure back type frame. Does anti-newton glass leave some kind of texture on prints ? So I don't use it anymore.

[doc]

do any of you have experience with making an 8X10 negative from a 6X6 negatitve? if I could I would like to know the particulars involved in this.