Filmscanners mailing list archive (email@example.com)
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
filmscanners: Re: Emulsion flaws
At 8:37 PM -0400 9/23/01, Austin Franklin wrote:
>I'm curious. Has anyone ever heard that this is a "problem" previously? I
>mean, film has been around for decades...as well as exceptional cameras,
>very good enlargers, and enlarging lenses...and people (including my self)
>have made some very large prints....but never have I heard anyone, out of
>hundreds of high end professionals and amateur photographers I know, ever
>mention "emulsion bubbles" as being a problem...
>I've also not heard any of the high end scanner people I know (who use drum
>scanners, Leafscans and Imacons) ever mention this issue either...
Yeah, I know. I'm curious, too. I made Cibachrome prints for
25 years on a Durst using Schneider lenses and never saw any trace of
them either. In fact, many of the older slides I'm seeing bubbles in
now were the ones I printed. I think it is a matter of focus - when
the emulsion is in focus, the bubbles are almost invisible.
Curiously, one slide in particular (Ektachrome 64 from 1979),
which I printed many times on Cibachrome and scanned using a Canon
FS2710, showed no particular flaws. When I got a new Minolta Scan
Dual II, I was shocked to see hundreds of specks and small lines in
the sky area. When I examined it under a dissecting microscope using
oblique light, all the marks showed up clearly. Most of them were in
the base side of the film rather than the emulsion side. This has
nothing to do with the present "bubble" discussion except to point
out that some things invisible to conventional enlargers do show up
on some scanners.
It also does nothing to explain why high-end scanners and
huge enlargements don't show the bubbles, either. I expect someone
out there will have an answer.
I started my investigation in response to a list member who
was getting hundreds of tiny spots in Polaroid SS4000 scans from
slides that seemed dust-free. I still think the "bubbles" are too
small to show up as discrete spots, but they may have an effect on
the "grain-aliasing" phenomenon.