Archived from groups: alt.comp.periphs.scanner (
More info?)
"Kennedy McEwen" posted
"...
How much depends on the film batch and the chemistry it was processed in - contrary to
popular belief, Kodak changed the Kodachrome manufacturing and development processes
several times over the years.
...."
True.
IIRC ... the process in use during the 1990's was called "K-14" ... and yes, that really
was (at least) the fourteenth major variation.
"Kennedy McEwen" <rkm@nospam.demon.co.uk> wrote in message
news:zud9GermDoGBFwqD@kennedym.demon.co.uk...
> In article <b76bbd04.0408110702.5b26625c@posting.google.com>, Brian2915
> <brian2915@yahoo.com> writes
> >I've read every message and review for the last 3 years on film
> >scanners and still can't make up my mind. I have a large number of
> >older kodachrome (some 20 years old) that I want to scan. I want the
> >best quality that I can get from these. The Nikon 5000 seems to have
> >the best quality overall, but a problem with kodachrome. How big a
> >deal is this really? Anybody have another recommendation for these
> >slides? I'd even consider then 9000 if that would give me what I want.
> >Thanks for your help.
> >
> How big a deal it is depends on how clean the slides are, because the
> "problem" only applies to ICE, the automatic cleaning facility, and even
> then it is only a problem with some Kodachrome emulsions and processes.
> The Nikon 9000 will have exactly the same problem to exactly the same
> degree, and the only real difference between the scanners is that the
> 9000 will handle larger formats than 35mm.
>
> ICE works by illuminating the film with an infrared source which is
> normally transmitted well by the emulsion layers, so that the majority
> of the resulting image is simply the dirt and damage on the film
> surface. This image is then used as a mask to screen out the dirt and
> damage from the rgb colour image. The advantage of the Nikon scanners
> is that this infrared source is just an IR LED, which operates in
> exactly the same way as the RGB LEDs that illuminate the film. This
> means that the IR cleaning image can be captured at the same time as the
> RGB image, in a single pass, with perfect registration between the two.
> Scanners which use white light and an rgb filtered sensor generally need
> two separate scan head passes because the IR source and the white source
> cannot be switched on and off fast enough to enable a single pass.
> Consequently there is the potential for misregistration between the IR
> cleaning image and the RGB image. To allow for this, the image is
> screened over a wider area around each defect, which produces a poorer
> result. So, the Nikon LED illumination system implements ICE much more
> successfully than other scanners.
>
> The "Kodachrome problem" occurs because the infrared light is not
> transmitted by the silver salts that form the image on conventional
> black and white films. So we start with the warning that ICE does not
> work at all on conventional black and white films. In most colour
> films, the silver salts that make up the image are dissolved out in a
> bleach bath, leaving only the colour dyes, which are fairly transparent
> to infrared, so ICE works with most colour films. Certain black and
> white films work in a similar way and are designed to be processed in
> colour chemistry, type C-41. These work with ICE as well, because the
> silver salts are removed.
>
> Kodachrome is a unique emulsion in that the silver salts are not
> guaranteed to have all been removed from the emulsion as part of the
> process. In particular, very dense images often contain a significant
> silver salt residue in the emulsion. How much depends on the film batch
> and the chemistry it was processed in - contrary to popular belief,
> Kodak changed the Kodachrome manufacturing and development processes
> several times over the years. Some of these combinations result in more
> silver being left in the emulsion than others, and it is a bit "hit and
> miss" as to whether certain films are compatible with ICE or not. Since
> you have a lot of Kodachrome, spanning many years, there is a good
> chance that some, perhaps most, of your film will be incompatible with
> ICE. However, if this is the case, you only need to switch ICE off -
> which means cleaning the sides carefully with a clean air blower before
> each scan and possibly spending some time retouching the residual dirt
> by hand afterwards. I was lucky in that I only had a few rolls of
> Kodachrome 25 & 64, and it turned out that these scanned fine even with
> ICE.
>
> Even without ICE enabled, you will be hard pressed to find a better
> scanner than the Nikon LS-5000 for your needs. Not only will it scan
> with 16-bits per channel, it has several features to improve its
> performance even further, including single pass multiscan. The scan
> speed of LS-5000 is extremely impressive - just 20secs for a full
> 4000ppi frame - and it accepts an optional bulk slide feeder. So,
> unless you enable a lot of post processing for each scan, you should be
> able to digitise your photographic records in less time than any other
> scanner on the market. Unless you want to wait another 3 years for
> something else to come along, you won't do any better.
> --
> Kennedy
> Yes, Socrates himself is particularly missed;
> A lovely little thinker, but a ah heck when he's pissed.
> Python Philosophers (replace 'nospam' with 'kennedym' when replying)
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