Re: filmscanners: Re: filmscanners: RE: filmscanners: Re: Rescans and archiving

[Arthur Entlich <artistic@ampsc.com>]

Kodachrome is a really odd dog.  As some my know, Kodachrome starts life 
in your camera as a rather complex black and white film, with color 
separation filters in between each sensitive layer.  It contains no dyes 
to form dye clouds, etc.  The E-6 films do contain the dyes that will 
eventually become the colors in the film.

Kodachrome dyes are added during the processing.  This makes Kodachrome 
both vulnerable to one or more of the dyes being off color, makes 
Kodachrome both expensive and involved, and makes Kodachrome 
environmentally a worse process.  Kodachromes literally have to be 
bathed in magenta, cyan and yellow dye baths to color the film at the 
time of processing.

The advantage of Kodachrome is that since the dyes are not part of the 
film, they can be designed to be more stable, and they are.

Art

Rob Geraghty wrote:

> Harvey wrote:
> 
>>Fuji's Velvia chrome film is the most stable of the Fuji
>>chrome films (significantly more stable than the rest).
>>I think that's he only one that is more stable than Kodak
>>Ecktachrome...But my knowledge is a few years old.
>>
> 
> Is there a relationship between stability and film speed?  I'm intrigued
> becuse Velvia is ISO50 and Kodachrome is generally ISO64. Yes I know about
> K25 and K200. :)
> 
> Rob
> 
>