Old K-12 Kodachrome as negatives

Gerald Koch · May 24, 2006

High sulfite concentration prevents the formation of the stain but does not effect it once it is formed.

Bleaching out the silver from a pyro negative was a standard technique used many years ago to produce a grainless image.

Photo Engineer · May 24, 2006

Gerald Koch said:
High sulfite concentration prevents the formation of the stain but does not effect it once it is formed.

Bleaching out the silver from a pyro negative was a standard technique used many years ago to produce a grainless image.

Ok, is an additional comment.

In all color products, holes are left where silver is bleached out. This can be seen in photomicrographs and in enlgargements and it is one of the 'goals' of the color system engineer to minimize those holes. The larger the grain of silver, the larger the voids formed when bleaching is done.

The tighter the dye particles around the silver grains, the more difficult it is to bleach the silver.

So, there are tradeoffs here. What you report may have been done years ago and the workers then may have thought the images were grainless, but were they? Has anyone done it recently?

I'm not disputing your comments BTW, I'm trying to add information to it based on my experience, and also trying to see if this has been done in modern times. Maybe the old work was done with LF negatives, and a modern repeat with t-grain films in 35mm might completely change this informaton. IDK, I have no idea.

PE

Donald Qualls · May 27, 2006

I managed to try B&W reversal yesterday, and did another roll today. So far, so good; more information here:

(there was a url link here which no longer exists)

r-s · Nov 3, 2006

Photo Engineer said:
Guys, silver is silver whether developed by a developer or coated in the coating as the CLS yellow silver layer.

They have different sizes and shapes as particle, some being threads, some being tablets and some being colloids (CLS yellow silver).

Using a bleach to remove one type of silver will inevitiably remove all or part of another type of silver and therefore you will destroy image silver along with CLS silver no matter what you do.

So, the only way to get a clear Kodachrome B&W with no image loss, is through reversal B&W processing. You can approach it in a negative process, but only with image loss to some degree, usually severe.

*************WARNING***WARNING***WARNING*************

I have NOT tried this technique! It may NOT work!

*************WARNING***WARNING***WARNING*************

But, then again, it just might!

I've wrestled with this issue -- how to develop a true silver negative, without the (silver) yellow filter layer, without degrading the negative image.

Why?

Good question. If anyone knows the answer, I'm all ears.

My first idea -- quickly discarded -- was to give a pre-bath in a B&W-reversal type bleach (permanganate or whatnot), to remove the CS yellow filter layer, without touching the undeveloped emulsion.

I quickly dismissed this idea when I realized that in addition to bleaching out the yellow layer, it would also eat away the latent image "seeds" in the undeveloped crystals, rendering the entire film "unexposed".

Oh well, would have been nice, but no cigar.

But then it hit me -- there is (I think ) a way to remove the yellow layer, and leave the actual negative content entirely unaffected!

What it would require is what I will call a "reversed-reversal" process.

First, develop the film normally (as a B&W film). This will give you a normal negative image, and, that accursed yellow filter layer will remain present.

Then, run the film through stop bath, and fixer, and then wash it. (In other words, up to this point, process it as if it were regular B&W film.)

Now comes the fun part: Turn the lights out (in other words, put the lid back on the tank).

Now bleach it with a rehalogenating (i.e., "color-type") bleach.

This will do two things. First, it will give you an "undeveloped" version of your negative (with the rest of the film "cleared" by the fixer), and, it will give you an "undevloped" version of the yellow filter layer.

Now the magic: Give the film a controlled re-exposure (you'll need to do a bit of trial-and-error to determine the correct amount of light to give it), and then, redevelop it.

This will once again give you two things: A developed silver negative, and, and UN-developed yellow filter layer! (You then run the film through stop bath and fixer, which removes the undeveloped yellow filter layer, then wash, and dry your negatives!)

How did that happen?

It's simple, when you think about it. The yellow filter layer is made from extremely tiny, microscopic silver grains. This means that even though they will be "light sensitive" when bleached, they will be much LESS sensitive than the actual negatives!

That's why a controlled re-exposure is so critical. You want to give enough light to re-expose the three emulsion layers, but NOT expose the much slower yellow filter layer. I would imagine that the amount of light necessary to cause the yellow layer to develop would be orders of magnitude greater than the amount necessary to expose the actual negative layers.

As I said, I haven't tried this, but I can't see why it wouldn't work. The key is that the yellow filter is made of silver grains that are many times less sensitive than the actual emulsion layers.

In a way, it's sort of like "doing a Kodachrome" on Kodachrome (or any color film using a colloidal silver yellow filter layer) -- selective re-exposure, to ensure that only the desired layers are developed.

Photo Engineer · Nov 3, 2006

The method I describe regarding reversal processing is mentioned elsewhere on APUG and has been tried. It works and gives reversal images.

The method described above by Ryuji will probably not work. The silver halide formed by the rehal bleach will form in a very fine crystal form determined by the form the developed silver is in, from tabular to filamentary. Therefore, it is a game of chance as to whether the silver haldies formed are sufficiently different in speed. The result would be a totally black piece of film with perhaps a very very faint image.

PE

r-s · Nov 3, 2006

I think we won't know for sure until there is empirical evidence. Somewhere I've got an ancient roll of Kodachrome II sitting around (in "leader hanging out" condition). and a couple of rolls of the previous Kodachrome (ASA 10), but those are in boxes, and I'm hesitant to destroy their collector value. (Just as I am reluctant to sacrifice one of my rolls of frozen K25 for an experiment.)

OTOH, it might be fairly easy to test the theory using a different film that uses the CS yellow filter. Don't most E6 films use that type of filter?

I must confess to not remembering what tactic Ryuji presented (I know I read the whole thread, but it's late, and I'm exhausted.) I am fairly certain though that my method would work nicely.

I know it's simple enough to process Kodachrome as a B&W slide, but the subject of this thread is processing it as a negative, and I think that's what most people would rather end up with (otherwise Scala would have driven Tri X off the market years ago, and Kodak would be selling their B&W reversal kits with brick after brick of Panatomic X to go with them.)

Photo Engineer · Nov 3, 2006

r-s;

Ryuji says processing as a slide will not work.

He suggests that processing as a negative, followed by a rehal bleach, controlled re-exposure and redevelopment will work.

I agree with you and others that reversal processing will work, but I doubt that his method will work due to the uncertainty of the form the rehal silver halide will take.

Therefore, IMHO, processing to a negative is going to leave a yellow filter layer behind along with the negative if you want to get the best possible image and scanning of the yellowish negative is probably the best way to retrieve the image.

PE

r-s · Nov 3, 2006

Photo Engineer said:
Ryuji says processing as a slide will not work.

LOL! I'm certain that will come as a great shock to the many people who have been doing it for years! Has he contacted Rocky Mountain Labs to tell them to stop offering the service?

Photo Engineer said:
He suggests that processing as a negative, followed by a rehal bleach, controlled re-exposure and redevelopment will work.

This is surreal. That is exactly the technique that occured to me, which I detailed a couple of posts above this, in this thread.

Do you have a link to the thread where he posted that? I'd be curious to see what steps he proposes, and any commentary it elicited.

Photo Engineer said:
I agree with you and others that reversal processing will work, but I doubt that his method will work due to the uncertainty of the form the rehal silver halide will take.

Therefore, IMHO, processing to a negative is going to leave a yellow filter layer behind along with the negative if you want to get the best possible image and scanning of the yellowish negative is probably the best way to retrieve the image.

PE

I think it's probably do-able, with caveats, primarily some testing to determine the correct re-exposure level and duriation for various films. I still think that the difference between the two grain types will be significant enough to provide a large gap in sensitivity levels. I've seen lots of B&W reversal film (I have been visiting this planet since the 1940s), and I know that I've seen plenty of grain. Therefore, I don't think it's a universal fact that the emulsion layers will be rehalo'd to something akin to the CS microscopic granularity.

I also recall having read in one of my books (an older book (maybe 50 or 60 years old) on emulsion design technique, which even gives instructions on "home-made" chromogenic color films!), which said that that there was research that revealed techniques for building B&W reversal films with two sets of emulsions blended together -- one high speed, larger grain, for "taking" (the negative) and another, very slow, fine grain, for the reversal development. Even if Kodachrome (or an E6 film) uses a similar strategy, it won't matter insofar as "my" technique is concerned, since that reversal "set" of grains will be washed out by the fixer without ever having been developed at all.

Edited to add that the only reason for the aforementioned B&W reversal "dual emulsion blend" technique would be to prevent the larger "taking" grains from displaying in the projected (reversed) image. Therefore, the grains do NOT characteristically reduce in size during rehalogenation. Q.E.D. (If they did, there would have been no need to figure out how to blend in a separate set of fine-grain crystals for the reversed image.)

CRhymer · Nov 3, 2006

Hello PE and r-s,

I have very nice B&W slides from Kodachrome - perhaps not Scala quality, but very decent (they also project very well - the acid test). I would use it more, but at almost $9.00CDN/roll for 36 exp. 35mm Kodachrome 64, there are other less expensive films that give decent B&W slides. However, Kodachrome is really an amazing film in many ways. But to the question of Kodachrome as B&W negatives: The CLS is problematic, but not impossible to print through. r-s, why use old film, which you may want to keep for collector value, when fresh dated K64 is available and not that expensive. It would eliminate issues of fog, loss of speed, etc. I have used re-hal bleach on Kodachrome and colour neg film developed as B&W negatives, albeit not with controlled re-exposure. The result, as PE has noted, is the replacement of the yellow/orange layer with black (actually more like a gray fog). The image was still quite good, but I concluded that it was easier to print trough the yellow CLS than the fog, and so went on to other things.

I also tried to partially bleach (dichromate, since one has to be able to see the progress), which removes the CLS quite quickly, but only partially degrades the image. Sulphite halts the bleach quickly. Since the there are multiple layers, it is possible that some layers are more degraded thus changing the effective spectral response. I gave this up, since reversal works so well.

However, this does not mean your conjecture will not work. Perhaps, since I have a perverse desire to pursue hopeless projects, I will give it a try.

I do not have a scanner, and have no experience in using one, but I have a friend in the business who does a lot of scanning. He scanned one of my negative images with the CLS layer and did his best adjustments in Photoshop. The result was no better than printing onto Kodak MG RC. Others may do much better.

Cheers,
Clarence

Photo Engineer · Nov 3, 2006

r-s said:
*************WARNING***WARNING***WARNING*************

I have NOT tried this technique! It may NOT work!

*************WARNING***WARNING***WARNING*************

But, then again, it just might!

I've wrestled with this issue -- how to develop a true silver negative, without the (silver) yellow filter layer, without degrading the negative image.

Why?

Good question. If anyone knows the answer, I'm all ears.

My first idea -- quickly discarded -- was to give a pre-bath in a B&W-reversal type bleach (permanganate or whatnot), to remove the CS yellow filter layer, without touching the undeveloped emulsion.

I quickly dismissed this idea when I realized that in addition to bleaching out the yellow layer, it would also eat away the latent image "seeds" in the undeveloped crystals, rendering the entire film "unexposed".

Oh well, would have been nice, but no cigar.

But then it hit me -- there is (I think ) a way to remove the yellow layer, and leave the actual negative content entirely unaffected!

What it would require is what I will call a "reversed-reversal" process.

First, develop the film normally (as a B&W film). This will give you a normal negative image, and, that accursed yellow filter layer will remain present.

Then, run the film through stop bath, and fixer, and then wash it. (In other words, up to this point, process it as if it were regular B&W film.)

Now comes the fun part: Turn the lights out (in other words, put the lid back on the tank).

Now bleach it with a rehalogenating (i.e., "color-type") bleach.

This will do two things. First, it will give you an "undeveloped" version of your negative (with the rest of the film "cleared" by the fixer), and, it will give you an "undevloped" version of the yellow filter layer.

Now the magic: Give the film a controlled re-exposure (you'll need to do a bit of trial-and-error to determine the correct amount of light to give it), and then, redevelop it.

This will once again give you two things: A developed silver negative, and, and UN-developed yellow filter layer! (You then run the film through stop bath and fixer, which removes the undeveloped yellow filter layer, then wash, and dry your negatives!)

How did that happen?

It's simple, when you think about it. The yellow filter layer is made from extremely tiny, microscopic silver grains. This means that even though they will be "light sensitive" when bleached, they will be much LESS sensitive than the actual negatives!

That's why a controlled re-exposure is so critical. You want to give enough light to re-expose the three emulsion layers, but NOT expose the much slower yellow filter layer. I would imagine that the amount of light necessary to cause the yellow layer to develop would be orders of magnitude greater than the amount necessary to expose the actual negative layers.

As I said, I haven't tried this, but I can't see why it wouldn't work. The key is that the yellow filter is made of silver grains that are many times less sensitive than the actual emulsion layers.

In a way, it's sort of like "doing a Kodachrome" on Kodachrome (or any color film using a colloidal silver yellow filter layer) -- selective re-exposure, to ensure that only the desired layers are developed.

r-s;

Here is Ryuji's post regarding my comment to process Kodachrome to get a B&W slide. It appears on the previous page here with a quote from my post on the subject.

I guess he doesn't know about this.

PE

Photo Engineer · Nov 3, 2006

Kodachrome's selective reexposure relies on retaining sensitizing dyes in the emulsion, not on size difference, therefore a rehal bleach, which forms an indeterminate type of grain, may have no discrimination between CLS and image silver.

This could give a uniform black with a faint image.

PE

r-s · Nov 3, 2006

Photo Engineer said:
r-s;

Here is Ryuji's post regarding my comment to process Kodachrome to get a B&W slide. It appears on the previous page here with a quote from my post on the subject.

I guess he doesn't know about this.

PE

Um.... I know I need coffee, but I'm drawing a blank here. You quoted my message, not Ryuji's.

I did a text search of this thread (it's all on one page as I view it), and the first mention of his name turns out to be in your post #30, which cites "The method described above by Ryuji", but there isn't any traffic from him at all above that post, so I am assuming you are referring to something he said in a different thread?

That's what I'd like to see -- his description of the process that I outlined earlier in this thread (which you quoted in your reply in #35, to which I'm replying now).

Can you point me to his description of this process? I've nosed around the forums for a while, but there are only so many hours in a day

r-s · Nov 3, 2006

CRhymer said:
Hello PE and r-s,

why use old film, which you may want to keep for collector value, when fresh dated K64 is available and not that expensive. It would eliminate issues of fog, loss of speed, etc.

Well, the reason I asked about whether E6 films used the same type filter layer is because I am sitting on some really sadly un-DMax'd E6 film (A brick-minus-one-roll of Agfa 1000 in 120, and some old Elitechrome). If initial tests with that stuff look like they're succeeding, then I'd think about putting some actual money into buying good film to experiment with. (This is a curiosity, not an obsession )

CRhymer said:
I have used re-hal bleach on Kodachrome and colour neg film developed as B&W negatives, albeit not with controlled re-exposure.

Well that, IMO, is the key. Without controlled reexposure, there's no way to test out the theory.

CRhymer said:
However, this does not mean your conjecture will not work. Perhaps, since I have a perverse desire to pursue hopeless projects, I will give it a try.

Let me know what happens if you do try it!

r-s · Nov 3, 2006

Photo Engineer said:
Kodachrome's selective reexposure relies on retaining sensitizing dyes in the emulsion, not on size difference, therefore a rehal bleach, which forms an indeterminate type of grain, may have no discrimination between CLS and image silver.

I'm well aware of the process steps in Kodachrome (both the original selective bleach (silver and dye) used for a short while in the '30s, and the current selective reexposure system).

I don't think you quite understand what I was getting at, as you seem to be attacking points I never made. In other contexts, this might be considered a strawman tactic.

Photo Engineer said:
This could give a uniform black with a faint image.

This is speculation, conjecture, and shall remain so until such time as actual experiments are attempted. Are you going to go all the way now, and forbid me to conduct some tests?

CRhymer · Nov 3, 2006

r-s said:
Well, the reason I asked about whether E6 films used the same type filter layer is because I am sitting on some really sadly un-DMax'd E6 film (A brick-minus-one-roll of Agfa 1000 in 120, and some old Elitechrome). If initial tests with that stuff look like they're succeeding, then I'd think about putting some actual money into buying good film to experiment with. (This is a curiosity, not an obsession )

I know this isn't quite answering your question, but C-22 and C-41 do. At least similar enough that my trials on Kodachrome and colour neg. film had very similar results. Another reason to start off with C-41 or E6 is one doesn't have to remove the remjet, which I find a total PITA. Got a roll of Fujichrome 120 RAP in front of me just begging to give its life for scientific experiments. Maybe I'll start there.

Cheers,
Clarence

Photo Engineer · Nov 3, 2006

r-s said:
Um.... I know I need coffee, but I'm drawing a blank here. You quoted my message, not Ryuji's.

I did a text search of this thread (it's all on one page as I view it), and the first mention of his name turns out to be in your post #30, which cites "The method described above by Ryuji", but there isn't any traffic from him at all above that post, so I am assuming you are referring to something he said in a different thread?

That's what I'd like to see -- his description of the process that I outlined earlier in this thread (which you quoted in your reply in #35, to which I'm replying now).

Can you point me to his description of this process? I've nosed around the forums for a while, but there are only so many hours in a day

Sorry, that was your message. I misquoted.

It was your post and your process.

PE

Photo Engineer · Nov 3, 2006

Ok, now that I have gotten myself straightened out, here is the question for r-s.

If the reversal processing of Kodachrome works, then why the ***warning***?

It does work and there is no question about that. We seem to agree.

Now, as for other reversal films. Well, really, all reversal films will go through a reversal process with a NON REHAL bleach to give a reversal image. In fact, any film will.

As for films with CLS layers, they will probably not tolerate the selective reesposure process that r-s advocates due to the lack of speed and spectral discrimination between layers. Now, I admit that this will take experimentation. I believe I did use a conditional on my initial statement, but the probable result is based on over 50 years experience in photography.

My bet is it will not work.

PE

MMfoto · Nov 4, 2006

My question in all this is: Would these non K-14 processes work for someone who exposed an orphaned Kodachrome emulsion intending to develop it traditionally, or would some drastic change in EI and contrast result?

Photo Engineer · Nov 4, 2006

With a proper development, and no age related problems, the emulsion should give full speed and reasonable fog, however reversal emulsions are designed for higher fog as I mentioned elsewhere. The contrast would be something else again.

Therefore, a reversal B&W process is probably to be preferred. Assuming you mean B&W processing.

Perhaps someone out there has tried it recently and can give us more information on all of this.

PE

Ottrdaemmerung · Dec 5, 2010

This thread is a little too technically involved for my very small brain, so I require only a simple answer.

A friend has a roll of K-12 process Kodachrome II from a camera belonging to a late relative, and she'd like me to process it. I can do basic tank processing in B&W chemistry, or C-41. As far as I'm aware, Dwayne's Photo will only process K-14. My question is whether I can obtain a visible, scannable image by developing K-12 process film in B&W chemistry like Rodinal or D-76, like I can with C-41 film.

Thanks in advance for any information!

r-s · Dec 5, 2010

The problem you will run into is the yellow filter layer in Kodachrome is made of metallic silver and silver salts (Carey Lea Silver, finely divided metallic silver, and the silver salts, act as a yellow filter).

After first developer (the K14 process ironically uses a phenidone developer, the formula is available, a web search should turn it up for you, I don't have a URL handy, but most likely any decent film developer would work), you will have a black and white image on the three "color" layers, and, probably a very faint B&W image on the yellow filter layer (the silver salts are very fine grain and thus probably extremely slow, I'd guess about as fast as enlarging paper, or, maybe even slower, who knows).

You will also have the metallic silver from the yellow filter layer. The result is that you will have a dark overall "fog" -- separate from the actual image -- in the yellow filter layer.

I think some people subject the film to a brief bleach step, to remove the yellow layer (or more correctly, to turn it back to silver salts). However, it's IMPOSSIBLE to do this and NOT affect the REAL image layers too. However brief, if it's strong enough to bleach ANY silver, it WILL attack your shadow detail.

Thus, the favored approach is reversal processing, which CAN neatly remove the silver from the yellow filter layer and NOT attack the actual image.

Ottrdaemmerung · Dec 5, 2010

Okay, so does this mean I would have much better luck trying to process the film with E-6 chemistry instead of B&W?

Photo Engineer · Dec 5, 2010

E6 chemistry used on Kodachrome will give blank clear film.

PE

Old K-12 Kodachrome as negatives

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