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  1. #31

    Join Date
    Sep 2009
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    I couldn't get hold of an original Durst AN glass so I sent off to Focalpoint for one.

    I put various negatives in my normal glass carrier to try out and they were covered in newton's rings. I always used to use a glassless carrier for 35mm and it seemed fine and can still do this if I fancy. I think I will make some up for 6x6 out of 2mm aluminium plate and see how I get on.
    Dave

  2. #32

    Join Date
    Oct 2004
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    Fond du Lac, Wisconsin
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    I have a Screen Cezanne scanner, a large pre-press machine. According to an independent test, the Seybold report, it is capable of resolving 5600 spi, or a little more. It's scanning bed is what looks like 6mm thick acrylic with a very fine anti-newton texture. Convinced that scanning through the anti-Newton texture would harm sharpness, I made an optical glass carrier. In order to avoid Newton's rings, I had to wet mount to the glass using Kami. After all of that work, I compared hi-res scans. The optical glass with wet-mounting was no better than scanning through the anti-newton acrylic. At that resolution, the files would make huge prints, much bigger than I'd ever print 35mm negatives. My point is that all anti-newton surfaces are not the same quality, and it's worth testing something even if there are theoretical reasons as to why it might not be ideal. If you get Newton's rings between the emulsion of the negative and the lower glass, by all means try out the highest quality AN glass that you can find. It might lead to an unacceptable loss of sharpness at your required enlargement size, but then again it might not.

  3. #33
    dwdmguy's Avatar
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    Feb 2009
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    Freehold, NJ
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    819
    Do you guys know where I can buy bulk ANR glass please?
    Thaks

  4. #34

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    Oct 2004
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  5. #35
    Maris's Avatar
    Join Date
    Jan 2006
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    Noosa, Queensland, Australia.
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    Peter De Smidt is right when he suggests that all anti-newton glass is not the same.

    A really inexpensive glass with perfect anti-newton properties is non-glare picture frame glass. This stuff has a subtle but easily seen texture that suggests that it would not work in an enlarger but it does; sort of. I make negative carriers using this glass as the top glass and I leave out a bottom glass. A film negative wants to pop upward when the heat from the enlarger hits it. A top glass prevents this. A bottom glass really has nothing to do except gather dust or perhaps prevent the negative falling into the enlarger bellows.

    An enlarger with a strongly collimated illumination system, a condenser or point light design for example, will image the texture of anti-glare picture frame glass. My Durst 138S enlarger certainly does.

    A semi-condenser or diffusion system enlarger won't image anti-glare glass. My Omega D2V certainly does not. And if I put a diffusing screen into the light path of the Durst 138S it doesn't image anti-glare glass either!

    So, beating newton rings is easy and cheap for me but only if I am prepared to accept a significantly diffused light source in my enlarger. So far, so good.
    Photography, the word itself, invented and defined by its author Sir John.F.W.Herschel, 14 March 1839 at the Royal Society, Somerset House, London. Quote "...Photography or the application of the Chemical rays of light to the purpose of pictorial representation,..". unquote.

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