[rollei_list] Re: Anti Newton Ring Glass Effect on Enlarging

You must introduce a slight distance between the negative and the negative clear glass. This can be done with a piece of masking tape placed on the edge of the clear glass negative carrier out of the image area. Or use an anti newton ring carrier which introduces the distance by itself. Are you using a Durst enlarger...an old one would have this problem?
 
Ed Meyers
-------------- Original message from Don Williams <dwilli10@xxxxxxx>: --------------


> At 08:00 PM 5/28/2009, Elias wrote:
> >Hi All,
> >
> >I think this question is best for all the optics aficionados here:
> >My enlarger uses AN glass above the neg, and clear glass below. With
> >my b&w Rollei negs this works very well, but with color negs not
> >well at all. Even though the emulsion side is in contact with the
> >clear glass, I still get rings. I'm thinking of getting another
> >piece of AN glass for below the neg. (emulsion side). Will that have
> >any effect on the projection, and the resulting print?
> >
> >Thanks,
> >
> >Elias
>
> It all depends on the texture of the color neg. My ANR experience is
> based on glass mounts for 6X6 projectors, and of course I have tried
> all combinations, however color positives are not as smooth as color
> negs. I got the best results with ANR glass on both sides,
> particularly in theater-size high power projection systems that would
> eventually cook the slide.
>
> Why not just get another piece of ANR glass for the
> bottom? Alternatively, experiment by exchanging the glasses and
> observe the result. You could also just examine what happens when
> you put the neg in emulsion up.
>
> I think it will depend on the depth of focus of your enlarger as to
> whether the ANR glass distorts the projected image.
>
> Can you see the rings on the paper holder or only on the print?
>
> What happens when you use B&W paper with color negs?
>
> In the olden days a little dusting of corn starch, or something
> similar did the trick.
>
> Good luck.
>
>
>
>
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