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

[Roger Smith <rsmith@unb.ca>]

At 9:06 AM +0100 9/21/01, Alan Tyson wrote:
>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.

Alan,
        Thanks for the clip. I'll have to look more closely at mine, 
but I would say they are quite different. The photo I sent was 
magnified 400x with the microscope, but the bubbles are only visible 
as a general "grittiness" in the background on a 2820 ppi scan - 
maybe only 3-4 pixels each. See the enclosed clip and blow it up on 
your screen. When I compared an area of the scan with the same area 
as seen under a dissecting microscope, the more obvious specks do 
seem to match the larger bubbles.

At 9:06 AM +0100 9/21/01, Alan Tyson wrote:
>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.

        Sorry - I was misleading. I meant I mixed the final rinse 
using double distilled water.

Regards,
Roger

Attachment: bubble-grit.jpg
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