Re: filmscanners: Glass slide mounts

["Peter Marquis-Kyle" <petermk@optushome.com.au>]

Neil Cotty wrote
> One side effect though, maybe someone can tell me why this is happening.
> With a few slides, say 10%, I am getting this erm, multi-coloured circles
> and unusual shapes appearing on the slide. I guess it is the film itself
> perhaps slightly curved, and light playing tricks - or could it be some left
> over residue from development? It does look like a liquid! Odd, but even so,
> if it happens I just use a std slide mount instead as it does show up in the
> scan. Ideas?

Sounds like "Newton's Rings". Here's a definition of this phenomenon (quoted
from a Kodak web site):
"Concentric bands of colored light sometimes seen around the areas where two
transparent surfaces are not quite in contact are referred to as Newton's Rings.
The rings are the result of interference and occur when the separation between
the surfaces is of the same order as the wavelength of light. "

> Lastly, the Quickpoint slides seem to have a matt side, the viewing side. I
> didn't like the look of that interferring with the scans so mounted them
> reversed. Any issues with that? Having never used glass slide before - is
> that there for projection?

My guess is that the matt side of the glass has an "anti newton's rings"
treatment -- put that side in contact with the film.

Cheers

Peter Marquis-Kyle