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Photo Forum / Film Photography / Darkroom / May 2005Coated glass for 8x10 neg carrier?
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?  SignatureThor Lancelot Simon tls@rek.tjls.com "The inconsistency is startling, though admittedly, if consistency is to be abandoned or transcended, there is no problem." - Noam Chomsky 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. >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. 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. SignatureThor Lancelot Simon tls@rek.tjls.com "The inconsistency is startling, though admittedly, if consistency is to be abandoned or transcended, there is no problem." - Noam Chomsky >>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 [quoted text clipped - 4 lines] >You can't use anti-newton glass under the negative; the texture of the >glass will show on the print. 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 ... Signature- Helge Nareid Nordmann i utlendighet, Aberdeen, Scotland For e-mail, please use my initials with the same domain as the posted address Website: http://www.nareid-web.me.uk/ > In an old article on Ron Wisner's web site he recommends using coated > optical glass in contact printers instead of anti-newton glass. > .... Does anyone know where to get this stuff? 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. SignatureNicholas O. Lindan, Cleveland, Ohio Consulting Engineer: Electronics; Informatics; Photonics. To reply, remove spaces: n o lindan at ix . netcom . com psst.. want to buy an f-stop timer? nolindan.com/da/fstop/ >> In an old article on Ron Wisner's web site he recommends using coated >> optical glass in contact printers instead of anti-newton glass. >> .... Does anyone know where to get this stuff? > >I have seen anti-reflective coated glass used for picture framing. >You might try searching the framing supply shops. 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. >FWIW, you don't need optical glass -- float glass (a.k.a. window glass) >will work fine. 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. SignatureThor Lancelot Simon tls@rek.tjls.com "The inconsistency is startling, though admittedly, if consistency is to be abandoned or transcended, there is no problem." - Noam Chomsky > I've actually had trouble with the quality of window glass in contact > printers. I regularly see sheets with small bubbles and the surface [quoted text clipped - 7 lines] > The Edmund product is 3.3mm which if I did my math right is a little > over 1/8", the standard window glass thickness. 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. SignatureJ www.urbanvoyeur.com >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. If I could get thicker, tempered, *coated* glass, that would be perfect. Now, do you know where I can get glass like that? SignatureThor Lancelot Simon tls@rek.tjls.com "The inconsistency is startling, though admittedly, if consistency is to be abandoned or transcended, there is no problem." - Noam Chomsky >>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" [quoted text clipped - 3 lines] > >Now, do you know where I can get glass like that? 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. SignatureThor Lancelot Simon tls@rek.tjls.com "The inconsistency is startling, though admittedly, if consistency is to be abandoned or transcended, there is no problem." - Noam Chomsky 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. >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. 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 See www.fpointinc.com/lighthouse.htm for enlarger glass. He has a wide assortment of types and sizes. Bob AZ >I cannot, however, figure out where on earth he got his hands on even >an 8x10 sheet of anti-reflection coated plain glass. 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 |
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