[pure-silver] Re: AN Glass Effect on Sharpness

RobC wrote:

Not all AN glass is equal. The Durst An glass for my L1200 actually throws a 
pattern from the glass onto the print if I look very carefully. And that is 
when it is above the neg. For sure it would reduce the quality of the print by 
making it unsharp. You can call it glass but if it's under the lens then it is 
a lens. I bet you wouldn't put a rough surface filter on your taking lens would 
you. At least unless you wanted soft focus. Mind you, the effect may be 
pleasing on some prints. Suggest you try it and see for yourself.

RobC
The emulsion side of older film tended to be less glossy than some newer films. As such, the newer film can give Newton's Rings on both the base and emulsion side. Howard Bond ran into this problem with 4x5 TMX. As a result, he used AN glass both above and below the negative, and he couldn't see any degradation at the enlargement sizes that he uses.
I have an 8 year old Screen Cezanne scanner, a high-end scanner which was in the tens of thousands of dollars new. It has an acrylic bed with a very fine anti-Newton texture. Convinced a priori that it would lead to a loss of resolution, I build a replacement tray out of optical glass. Even at the highest resolution, well over 5000 spi, I couldn't see any difference between a wet-mounted slide on optical glass, a wet-mounted slide under the glass with only mylar and Kami fluid between the emulsion and the lens of the scanner, and a negative placed on the finely-textured scanning bed. These scans would've produced huge prints.
So, some anti-newton surfaces don't lessen resolution to any noticeable degree, whereas coarser textured glass certainly would.
Another option would be to wet-mount the negative to the glass using mineral oil. It would be messy, but it certainly can be done. There even used to be special negative carriers made specifically for using oil. (I think these were often used with micro film and point light sources.) Don't use drum scanning fluid for this, such as Kami, as it is flammable. 
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