Re: filmscanners: Emulsion flaws (was dust in SS4000)

["Alan Tyson" <AlanTyson@bknowl.freeserve.co.uk>]

Roger,

I have seen something similar recently (5K Scanwit/Vuescan
positive clip attached) on a neg film processed in a
brand-new Kodak minilab in my local Tesco store. The bubbles
on mine are about 140 microns diameter (15pixels @ 2700ppi),
but I can't tell the size of yours without knowing how the
pixels on your Coolpix at 400x relate to the real world. I
note that I've got some lenticular shapes, and yours are all
circular in profile, so maybe they're different phenomena.

I attributed it to air bells, and haven't used that minilab
since. In fact, having seen the insides and watched the
routine maintenance of some minilabs when I worked on their
waste treatment a couple of years ago, I don't normally use
supermarket minilabs at all.

Are you sure your final double-distilled rinse is a good
idea? When I did my own 20yrs ago, wetting agent was deemed
necessary to give an even liquid film during drying.

Regards,

Alan T

----- Original Message -----
From: Roger Smith <rsmith@unb.ca>
To: <filmscanners@halftone.co.uk>
Sent: Thursday, September 20, 2001 9:33 PM
Subject: filmscanners: Emulsion flaws (was dust in SS4000)
........
> under my microscope and cranked up the magnification to
> 400x. The enclosed Nikon Coolpix 995 image taken through
the
> microscope shows what I saw. This is an area of the slide
which is
> almost transparent - the orange area at the bottom shows
the film
> grain. The bubble-like flaws are in a different plane from
the grain,
> on the outside layer of the emulsion. I can tell this by
where I have
> to focus the microscope to see them.
> I developed the film myself, using double distilled water
for
> the final rinse.............

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