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Photo Engineer
10-09-2008, 08:38 PM
Thanks Ralph, but I left out the Newton ring problems and everything else in my last post to make it look simple. Nothing every is, but a shake of talcum powder might help my last post out. :D

PE

michaelbsc
10-10-2008, 09:22 AM
The process uses a high pH color developer (~11 - 12) that is not very stable so you might consider it a one-shot. OTOH, the rest of the process is normal. So, if you pick a normal B&W film and process in the normal negative developer, then the rest of the process is a breeze.

PE

Well, the high pH doesn't really bother me, and unless the one-shot cost is prohibitive using it that way makes perfectly good sense to me. After all, I use B&W developer one-shot, and the thread about one-shot fixer has me thinking, too. What's the harm in adding a one-shot color developer.

Can you point me to a few references about how this is done?

My first thinking is that there has to be a 3 part separation, and the cheap way, if the filters are the right colors, is to just buy an old dichronic head when one goes by on fleabay and steal the filters out of it. Of course, I don't know that those are the right colors for the separation. They might be the complimentary colors instead of the ones required.

Another thing that confused me in a few of the Google hits I found last night was the references to two part Kodachrome instead of three part. I guess it was something like red and green layers the way some laser displays have a red and green laser. Can you really get all the colors from that? If so, then it seems you could get a complete transparency in a single film holder. Two exposures and your ready to roll.

Obviously this isn't going to be any good for the horse races since at present I'm not thinking of ways to shoot all three simultaneously. I couldn't find anything helpful about robbing an old three color prism from ancient TV cameras with Vidicons, and I don't think new TV cameras work that way.

I guess I'll have to get the models to stand still.

MB

Nicholas Lindan
10-10-2008, 10:09 AM
OTOH, maybe color was so novel to them they were awed! IDK. Try it!

I have a 1939 photography magazine (Minicam ?) where references to color photography involved 3-plate cameras and dye-transfer printing. A standard joke was not knowing which way up to hold the camera.
http://johnsrolleionlypage.homestead.com/Bermpohl_color_nature_camera.jpg
http://www.vintagephoto.tv/research_help.shtml

Though, IIRC, projection was the usual method of viewing:
http://www.spira.com/spira%5Chome.nsf/ItemView?OpenForm&SRC=927675F16F79128E85256B200063176E~~2272.jpg

Neat article on early color, including Prokudin-Gorsky
http://sechtl-vosecek.ucw.cz/en/expozice5.html

Ian Grant
10-10-2008, 10:21 AM
It's worth reading D.A.Spencer, Colour Photography, ? late 1940's, he give a good breakdown of all the colour processes including tri-colour etc.

Ian

Photo Engineer
10-10-2008, 10:50 AM
Tri color cameras are quite popular on the dye transfer forum:

http://tech.groups.yahoo.com/group/dyetransfer/

and dye transfer is described fully here:

http://www.dyetransfer.org/

Methods are described in "History of Color Photography" by Friedman.

The 3 color developers are available in kit form from some dealers. Ian has posted the reference in several threads here.

PE

htmlguru4242
10-10-2008, 11:12 AM
As to color developers, can't say that I have any idea about the Kodachrome ones, but Rockland Colloid sells a dye-coupler / color developer product intended to tone paper. It's called polytoner, I believe. I'd imagine that with experimentation, it could be applied to this fairly easily.

Kirk Keyes
10-10-2008, 11:20 AM
My first thinking is that there has to be a 3 part separation, and the cheap way, if the filters are the right colors, is to just buy an old dichronic head when one goes by on fleabay and steal the filters out of it.

Just get some Wratten tri-color separation filters:
http://www.motion.kodak.com/US/en/motion/Products/Lab_And_Post_Production/Kodak_Filters/wratten2tbl.htm

I think you want #29 Red, #47 Blue, and #61 Green. Your favorite camera store should be able to get you these filters, either in gels or in glass.

pjwaffle
10-12-2008, 06:37 PM
Hi, thanks for all the replies! Kodachrome seems scary, is there a B&W commercial emulsion formula available?

Thanks,
Joe Moo

Photo Engineer
10-12-2008, 07:04 PM
Yes Joe;

This formula has several generic formulas listed. Just search.

PE

tiberiustibz
10-13-2008, 11:50 AM
Say I were to process kodachrome with e6 chemistry but add in couplers. I would do test re-exposure strips to check when more time showed little difference in the re-exposure, first cyan/red re-exposure and then the yellow/blue one and white light instead of chemical fogging. What problems would I run into? Also, can a normal base like ammonia be used to remove a remjet backing or does it require a stronger one?

Photo Engineer
10-13-2008, 11:59 AM
Yes, the E6 process might work if you use 3 color developers and 2 reversal exposures. You cannot use ammonia, you must use sodium carbonate.

Process:

carbonate-rem jet removal
wash
1st developer
wash
red reexposure through base
cyan developer
wash
blue reexposure through emulsion side
yellow developer
wash
fogging bath
magenta developer
wash
bleach
wash
fix
wash
stabilzer

The color developers would be an E6 developer split into 3 parts. IDK if it would work.

PE

AgX
10-13-2008, 03:32 PM
As a side note:

It is interesting that the project did not start with selective-light-fogging from the start but run for about three years with the delicate selective-bleach process.

Seemingly there was that issue of cross-talk whilst exposing to coloured light. As PE already indicated the green sensitive layer is not light-fogged as one would expect, but foggged chemically.

Another hint is that Ilford’s none-substantive (couplerless) chromogenic colour film of 1947 (the ’57 version too?) has got interlayers that are pre-fogged and build up density in the first developing stage. These are to protect the green-sensitive layer from the two fogging exposures aimed at the other two layers. Thus even white light could be used.
Though, it might be that it rather was a patent issue…

AgX
10-13-2008, 05:16 PM
I just reread papers containing informations from Ilford. Ilford stated that they had not the means to go the Agfa way and thus had to try to evade Kodak patents.
They did so beyond the '57 version of the Colour Film up to the '60 Ilfachrome. They went the actual Kodachrome way in the '62 Ilfochrome as Kodak patents had expired by then.