I load the SS4k slide/film holders up and then look at them under a large
Luxor lamp/magnifier as I blow off any visible dust. The lamp really makes
any dust stand out. When the film is clean, I keep the film holder held on
edge until it gets to the scanner and is inserted. Even with these
precautions I can see significant amounts of dust when the scan is greatly
magnified. I've come to the conclusion that almost all of it embedded in the
emulsion and results from sloppy processing labs with no filtering of their
solutions. Some labs give MUCH better results than others from the
cleanliness standpoint as well other areas.
Cliff Ober
-----Original Message-----
From: owner-filmscanners@halftone.co.uk
[mailto:owner-filmscanners@halftone.co.uk]On Behalf Of jimhayes
Sent: Wednesday, September 19, 2001 9:48 AM
To: filmscanners@halftone.co.uk
Subject: Re: filmscanners: Dust in Sprintscan 4000?
In my SS 4000 35 mm frames, which are mainly Tmax 100, I did a rough count
once. I chose moderately (one stop) underexposed negs or night shots, so
white
dust specks/hairs would show up. I scanned with Vuescan at 16 bit straight
through to photoshop and enlarged to 100% and went around the frame and
counted
dust specks. I live in a semi-arid area and humidity ranges from 20-50%RH. I
store the negs in mylar sleeves, thumb cut from the side from "Light
Impressions" (and stored in their folder/ box system) to avoid insertion
scratches. I shoot each neg with an anti-static gun, and compressed air from
a
rather healthy air compressor (not damaging neg, however), and I wear high
quality cotton gloves. Then I examine negative at an angle under good
lighting-
and I almost never see any dust remaining on neg (keep reading tho). I keep
an
air cleaner (HEPA) in the room 24/7, overated for the size of room, and I
keep
the door closed with a seal on the bottom, and all windows closed, except a
permanently window mounted air conditioner. Yada, yada...
The count varies from 200-1000 spots per frame. I think a lot is due to dry
climate and the increased resolution of scanner, or maybe I should circulate
the air more than I do. The highest numbers come from a processing lab in
Utah
(dip and dunk). The lowest numbers come from rolls I have processed myself
(I
used a 2 micron water filter at one point) or even better, a little outfit
in
New Mexico which actually still does roll tank processing, with fresh
solutions, etc, specializing in B&W only. Since I am VERY low volume, I
don't
mind spotting away for two hours or more, as long as I can get up every half
hour to take a quick screaming break.
Hopes that helps.
--
Jim Hayes
Digital Surrealism
Images at
