Coated glass for 8x10 neg carrier?

Discussion in 'Darkroom Developing and Printing' started by Thor Lancelot Simon, May 3, 2005.

  1. I have a Durst 10x10 enlarger with an Omega colorhead. It's big, bulky,
    hard to align, loud as a jet engine and bright as a searchlight: I love
    it.

    The only thing I don't love is that its weird hybrid head uses an
    obscure Durst negative carrier system that is not the usual one found
    on the Laborator 184. So I am pretty much limited to the negative
    carrier which came with the beast, which is an 8x10 glass carrier with
    one sheet of Anti-Newton and one sheet of clear glass (AN on top, clear
    on the bottom, of course).

    I have a small number of negatives which show newton rings with this
    system no matter what I do. I've tried adjusting the humidity in the
    room, adjusting the pressure on the negative carrier from the enlarger
    head, shimming the carrier so the glass doesn't rest directly on the
    negative; no luck.

    In an old article on Ron Wisner's web site he recommends using coated
    optical glass in contact printers instead of anti-newton glass. He
    says that this reduces the amplitude of the newton ring reflections
    so much that they are usually not detectable on the print. It seems
    like this material would be *perfect* for the bottom sheet of glass
    in my negative carrier.

    I cannot, however, figure out where on earth he got his hands on even
    an 8x10 sheet of anti-reflection coated plain glass. Docter Optic
    used to sell 8x10 and 11x14 Zeiss optical glass but it was not coated,
    and I can't find any other source. I actually need a 10x10 piece.

    Does anyone know where to get this stuff?
     
    Thor Lancelot Simon, May 3, 2005
    #1
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  2. Thor Lancelot Simon

    RJM Guest

    Seller FE2000 was selling 8x10 AN glass on Ebay not long ago. She
    doesn't have any listed now.Do a search on FE2000 and send he a note
    asking if she has any more, and in any other sizes.
     
    RJM, May 3, 2005
    #2
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  3. I don't need anti-newton glass, I need anti-reflection coated glass.

    You can't use anti-newton glass under the negative; the texture of the
    glass will show on the print.
     
    Thor Lancelot Simon, May 3, 2005
    #3
  4. I have seen anti-reflective coated glass used for picture framing.
    You might try searching the framing supply shops.

    FWIW, you don't need optical glass -- float glass (a.k.a. window glass)
    will work fine.
     
    Nicholas O. Lindan, May 3, 2005
    #4
  5. I'd love to find that -- the common material used for framing around
    here seems to be lightly textured, not coated with a smooth AR coating,
    and if I could get framing-sized pieces, I'd swap out the glass in a
    lot of the framed photos in my house, too.

    Wisner claims that most "AN" glass is in fact the textured glass used
    as anti-glare glass for framing. I'm not entirely sure I believe that,
    but that's what he says.
    I've actually had trouble with the quality of window glass in contact
    printers. I regularly see sheets with small bubbles and the surface
    is sometimes not as good as I'd like, either.

    As it turns out, Edmund Optical sells float glass in sizes up to 10x12
    with a multilayer antireflection coating on both sides. If the coating
    is durable enough to stand up to darkroom use, this isn't even too pricy
    at $55 -- I guess I'll buy a sheet and find out.

    The Edmund product is 3.3mm which if I did my math right is a little
    over 1/8", the standard window glass thickness.
     
    Thor Lancelot Simon, May 3, 2005
    #5
  6. Thor Lancelot Simon

    UrbanVoyeur Guest


    You might want to get it a little thicker if your carrier can hold it.
    And heat resistant/tempered if you can. It will be a little "tougher"
    and last longer than standard float glass.
     
    UrbanVoyeur, May 3, 2005
    #6
  7. Thor Lancelot Simon

    Helge Nareid Guest

    I've already posted an answer on sci.optics. In short, if you can
    afford the cost, there are a number of optical manufacturers which can
    supply such components, such as Technical Optics on the Isle of Man,
    which I have used in the past:
    http://www.cvi-tol.co.uk/4598.html

    Expect to pay a lot of money, though ...
     
    Helge Nareid, May 3, 2005
    #7
  8. I'm using a coated glass product called "DENGLAS" for a negative carrier,
    in place of the AN GLASS. I think it works equally well as AN. Denglas
    is designed for picture framing, and some frame shops have it, or can get
    it. But I found a sheet at a glass wholesaler. I had to buy a full 32x40
    sheet, for about $35, but it was cheaper than ordering through a frame
    shop.
     
    resummerfield, May 4, 2005
    #8
  9. If I could get thicker, tempered, *coated* glass, that would be perfect.

    Now, do you know where I can get glass like that?
     
    Thor Lancelot Simon, May 4, 2005
    #9
  10. The answer is "Denglas AR Tempro" -- another poster in sci.optics pointed
    me at www.denglas.com and it seems like a good answer.

    Now I have to see what their minimum order size is.
     
    Thor Lancelot Simon, May 4, 2005
    #10
  11. Thor Lancelot Simon

    Bob AZ Guest

    Bob AZ, May 5, 2005
    #11
  12. Thor Lancelot Simon

    John Guest

    Easy. Light Impressions for one. Or just go to a framing store and ask for Den
    Glass or Tru View. Both are AR and that's what I use in my carriers. I think I paid $20
    for an 8X10 piece which I had them cut to 6X8 for my 5X7 head.

    JD - www.puresilver.org
     
    John, May 5, 2005
    #12
  13. Thor Lancelot Simon

    John Guest

    Much but remember that the framing shop guarantees that they will cut it to size.
    They had to cut 3 pieces for me as I took my

    JD - www.puresilver.org
     
    John, May 5, 2005
    #13
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