Anti- Newton ring glass source/supplier?

[Albrecht Namatdurer]

Am about to start tinkering with an 8x10 enlarger built up from all sorts of orphaned gear- but am stumped as to source of Anti-Newton glass- i would dearly love to find a supplier down here in Oz- but i reckon that will be hard one- So folks- any suggestions gratefully received

[Walter Calahan]

http://www.fpointinc.com/glass.htm

http://www.grayglass.net/glass.cfm/O...d/45/conid/211

http://www.betterscanning.com/

No Google in Oz?

[Maris Rusis]

Anti-Newton glass can be replaced by cheap anti-reflection picture framing glass. This stuff is only slightly more expensive than window glass and any trade glazier can cut it.

The catch is in the texture of the glass. If the enlarger uses a point light source, a highly collimated source, or a strict condenser arrangement the anti-reflection glass texture will come out in the photographs. An enlarger using a diffusion head or a semi-condenser head won't image the glass texture and all will be well.

I use anti-reflection glass in my Omega D2V and Gilkon enlargers (both 4x5) with complete success but the anti-reflection glass does not work in my Durst 138 5x7 enlarger or my Durst 184 8x10 enlarger unless I add a diffusing screen to the light path above the negative.

[Peter De Smidt]

There are different quality levels of AN glass, and as Maris points out what will work for the money depends on other things. Anti-Glare picture framing glass has a texture on one side. You can get it on both, but why? This stuff sucks for picture framing, as you'll lose lot's of contrast, but for using as AN glass in a diffusion enlarger, it usually works well, and it's by far the cheapest option. It definitely has a coarser texture than the AN glass from Focal Point.

[Eric Woodbury]

If you are using a coldlight with a neg holder sandwich of AN and clear glass (as in the Beseler 810 conversion), then consider making the top piece white plexi (i.e. moving the coldlight diffusor to the top of the neg, you don't want two diffusors with coldlight) and eliminate the AN all together. A diffuse surface cannot generate Newton rings. I hope that makes sense.

[Peter De Smidt]

Eric,

Are you sure about the plexi? It is a little shiny, and I seem to remember getting some Newton's rings when taping a negative to white plexi for scanning.

[Drew Wiley]

You will be sorry if you use acrylic or typical nonglare picture glass. Some types of optically coated glass work, but it all depends on the film itself, the type of light source, and the angle of indidence of the enlarger lens. I have spent a lot of time and
money figuring these things out, and over the years have accumulated glass samples from all over the world. There really is no substitute for high-quality anti-newton glass.
But if you don't choose to ship it from a US or EU source, you might try to locate an optically-coated nonglare framing glass, NOT an etched or frosted type. This must
be carefully cleaned like a lens and might not be adequate for supressing rings from very slick films like TMax or ACROS. High quality enlarger glass is worth every cent.
The Durst or Omega type is especially effective, but for some applications I have found
the Focal Point glass to be adequate.

[Albrecht Namatdurer]

thanks- all makes sense- have been to talk to my picture framer and he has offered to give cut to size pieces to try out
I just needed a direction to go in- and yes-

Hey and yes, Google does work in OZ - we just change the spelling to English

Albrecht