Archived posting to the Leica Users Group, 2003/02/13
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At 7:21 AM +0000 2/14/03, Gerry Walden wrote:
>Nathan
>
>I hate to correct you, but you give the impression that Kodachrome is grainy
>and that is why ICE doesn't work with it. My understanding is that ICE does
>not work with any film with silver in the emulsion, and Kodachrome is the
>only colour transparency film that has this.
>
>Regards
>
>Gerry
If you look at a Kodachrome slide from the emulsion side, you will
notice that it has an 'etched' look. I has a physically uneven
surface that is produced by the development process. It is this
surface that causes the IR channel in the Nikon scanners problems,
because the IR reflections and interference cause the scanner to
interpret these 'ridges' and 'valleys' the same way it interprets
dust, hairs and scratches.
The Ektachrome (chromogenic) type films have a very reduced version
of this, which the IR channel can handle.
If you scan some Plus-X and some Kodachrome 64 in a Nikon scanner,
which have very similar grain before development, you will notice
that the Plus-X will have a lot more problems with ICE than
Kodachrome. That is because the Plus-X still has the silver halides
in it, while the Kodachrome doesn't.
The silver and silver halides are removed from Kodachrome during the
development process. This is done in a different way than in the
Ektachrome type films, which are dye-coupler films with the dye
components incorporated in the emulsions at the time of manufacture
as compared with the dye insertion or replacement method of
Kodachrome.
- --
* Henning J. Wulff
/|\ Wulff Photography & Design
/###\ mailto:henningw@archiphoto.com
|[ ]| http://www.archiphoto.com
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