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

With drum scanning, a negative is taped to a plastic cylinder with a polyester cover sheet. There are special mounting stations for this, although one can do it manually. The result is that there is a layer of fluid, then the emulsion, more fluid, and then the polyester sheet. The fluid gets rid of Newton's rings, and it also might effect color and sharpness a bit, as well as minimizing grain growth in scanning. For example, a wet transparency looks more contrasty and more saturated than a dry slide. These latter effects depend a lot on the scanner. I noticed much more improvement wet-mounting bw graining negatives on a Canon 9950F consumer level flatbed scanner than on a Screen Cezanne, where there's minimal if any improvement. I believe that the Aztek site as a video on wet-mounting. Aztek is one of the last makers of drum scanners.
You can wet-mount with lots of stuff, but if you use anything with water in it, it will swell the emulsion. Drum scanners usually use either Kami fluid or Prazio's mounting oil. Kami seems very closely related to naphtha, and I know a knowledgeable guy who does use naphtha. But these latter solvents are highly flammable. You do not want to use them in the proximity of heat, such as in an enlarger head. Mineral oil works well, but of course it must be cleaned off of the carrier and the negative, but no matter what the scanning fluid makers tell you, you need to clean the negatives after their use anyway. This is easy to see. Immerse a negative in the fluid and hang to dry. Examine the negative. There will be a residue.
Anti-Newton spray or talc powder is simply another way to provide a fine texture between the negative and the holder glass. It is messier than anti-Newton glass, and if you're against any texture in the optical path between negative and print, then this should be just as problematic.
Ron Wisner claimed that anti-reflection coated glass minimizes the appearance of Newton's rings, which makes sense to me, as they are an interference pattern caused by the interactions of reflections between two shiny surfaces. The downside is the multi-coated glass can be hard to find, expensive and difficult to clean.
It's possible that Museum glass, which is anti-reflection coated picture framing glazing (i.e. glass for picture framing) would work. I don't know how delicate it is, though. 
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