[Frameworks] Kodachrome

[Nicole Baker]

I gotta say, the more I learn about photographic chemistry, the more I am
saddened that it has become such a rare, niche activity.  There's really
nothing else like it.

Nicole Elaine Baker
MFA in Visual Studies, 2019
Pacific Northwest College of Art
Hallie Ford School of Graduate Studies
*www.magiklantern.com <http://www.magiklantern.com>*




On Wed, May 1, 2019 at 7:25 AM Scott Dorsey <kludge at panix.com> wrote:

> > So, just for the fun of it let me ask, what happens if you process
> > kodachrome in C41 chemistry? Anything? Mud?
>
> Nothing, because all the cool stuff in C41 is in the film rather than in
> the processing.
>
> Each layer of C41 has the color dyes and couplers already in there with the
> silver halides and the sensitizing dyes.  On the top is the blue layer
> with no sensitizing dyes, then there is a deeply dyed yellow filter layer
> to block out all blue, then there are layers below sensitive to red and
> green.  The red and green layers are -also- unfortunately sensitive to
> blue (as natural halides are) so that yellow filter prevents them from
> getting them exposed by blue light.  It's not perfect and it doesn't block
> UV effectively, which is why occasionally pink flowers would photograph as
> blue on older Kodacolor emulsions.
>
> Anyway... so you expose the film and each of the layers gets a latent image
> appropriate to the color it's sensitized to, and you send it to the lab.
> It's first developed in an ordinary B&W developer to develop silver images,
> then a color developer connects the color dyes up to the silver.  The
> excess color dyes are removed in a clearing bath, the silver is bleached
> out,
> the dyes are stabilized, any residual silver is fixed just for stability,
> and the lights are turned on.
>
> Initially in the C-22 days these were done with multiple baths, but these
> days some kits have it down to just a developer/color developer and a
> blix.  Modern developing kits also do things like having multiple
> developers
> with different temperature sensitivities which compensate for one another,
> so you don't need the high precision water baths that you did when C-41
> first came out.
>
> One of the nice things have having split bleach and fix is that you can
> eliminate the bleach in order to leave a B&W image on top of the color dye
> image.  This gives you much lower saturation but about a stop greater
> sensitivity.  It's a useful effect to lower saturation but it was also used
> by press photographers in the seventies to get an extra stop out of the
> film.
>
> So... if you run B&W film through C-41... you get a B&W image... then it
> bleaches it away and you get a roll of blank film.  The color dyes don't
> get attached because they aren't there.  Same thing happens if you were
> to run Kodachrome or Agfacolor films through the C-41 machine.
>
> E-6 is a special case because the E-6 dye coupler chemistry is very similar
> to that of C-41 and they use the same color developing agent.  So you can
> cross process C-41 in E-6 chemistry and vice-versa and get an image, though
> your color rendition won't be anything approaching accurate.
> --scott
>
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