Making Commercial Color Separation Negatives of Transparencies for the Kodak Dye Transfer Process

For some reason I can't get my equations to display correctly. There is a (B) term on the bottom rows that isn't displaying correctly for some some reason. It doesn't display with brackets.

[C] [0.9195 0.0129 0.0676][R] [R]
[M] = [0.0874 0.7168 0.1959][G] = E *[G]
[Y] [0.0257 0.1190 0.8553](B) (B)

[C] [0.9195 0.0129 0.0676]^-1 [R] [1.0904 -0.0055 -0.0849][R]
[M] = [0.0874 0.7168 0.1959] [G] = [-0.1288 1.4509 -0.3221][G]
[Y] [0.0257 0.1190 0.8553] (B) [-0.0149 -0.2017 1.1265](B).


[C] [1.000 -0.063 -0.093]^-1 [R] [1.113 -0.052 -0.061][R]
[M] = [0.155 1.000 0.000] [G] = [0.173 0.827 0.000][G]
[Y] [0.137 0.228 1.000] (B) [0.152 0.189 0.658](B).

Where R, G, B are Red, Green, and Blue, respectively.

Lachlan Young said:

And 2234 isn't really meant as a separation film. 2237 is a separation film, intended purely for digital recorders and while 2238 could be used for direct separations, if it had any masking effects, they would be explicitly stated. It's the same with the old Separation Negative 1 & 2, they had wider uses than you assume, such that if they had masking onboard, Kodak would have needed to specify as such (not least because they'd probably behave rather like Agfacontour equidensity film as they were not intended for colour coupler development). You seem to assume that no one else but you has access to the relevant source materials, or to people who worked with many of these materials (albeit more in the print industry). If you really have meaningfully original source materials, publish them verbatim.

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No Kodak did not specify all characteristics Separation Negative Type I and II! The self-masking effect can be useful in the graphic arts field as well. I think Eastman 2234 is intended more for the archival market. And I'm not implying there was any color couplers in Sep. Neg. film; its developed with normal black and white developers, so no dyes (or colorless dyes) are formed.

Yes, I'm publishing some of my sources here. I discovered that Sep. Neg. films had those properties myself, though someone might have indicated to me there was some kind of masking effect.

DREW WILEY said:

You're twisting my words. I've made all kinds of highlight and other masks, and have experimented with various methods and films for generating tricolor separations which I certainly wouldn't recommend as ideal to others, and only used myself for "what if" experimentation. And I'm getting a bit tired of your "know it all" attitude, especially since I've been in communication over the years with DT veterans who have rather different approaches to the same kind of problems. And I most certainly don't appreciate you implying these helpful people are "lying" just because you find their specific proven methodology doesn't comply with your own hypothetical version. In fact, there's not a lot of difference from making highlight masks from Tech Pan than using the same film in 35mm for title slides, which was once commonly done, including by me.

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I asked specifically if you made (in DT separations) the kinds of highlight masks used in the industry, being the long range highlight, highlight, and specular (made photographically). I can safely assume you have not.

How do you characterize “helpful people” in the DT field? You tried DT once and don't have any interest in doing it ever again, if I understand correctly. If these DT veterans were so “helpful” why were you having problems that you decided to simply give up? Guy Stricherz (who died earlier this year), said most people will give up after 4-5 years. I believe the difference is that those trained at Kodak MEC knew how to use the system well and set up their own commercial operations.

How do you define a “proven methodology”? My criteria for a validating a method or technique would involve it being systematically conducted, proven empirically, and independently reproducible. I'm assuming you don't have any sensitometric data from these DT veterans.

What I'm trying to show here are techniques, procedures, methods, and processes once used in the DT industry that are not known to many on the outside. I can assume you were not aware of all of these.

Gosh you've got an unnecessary axe to grind, IB. I still have my DT supplies and equip. What I don't have is a lot of spare time, considering I'm juggling other processes too, including color tweaks with results often so satisfactory that it's hard to justify what is perhaps the last decade of my darkroom life bagging yet another learning curve. I have experimented with a number of things out of sheer curiosity. But I have more efficient ways to generate my own signature body of work without compromising quality.

In the course of that, I've developed all kinds of specialized masking tweaks AS NEEDED. But that doesn't mean they identically correspond to your imagined and historically incorrect notion involving a whole graduated series of progressive highlight masks. All kinds of improvisations occurred under special circumstances; some were no doubt invented on the fly. That does not mean they were routine by any means. And I could more easily tailor my own masking variations on demand, namely, using present films, not discontinued ones.

Frankly, you're not just beating a dead horse, but a dead unicorn, by overcomplicating everything. And you're making assumptions about "standard industry practices" which were actually all over the map, involving not only numerous alternate routes, but even different sources of dyes and related materials.

If you choose to be one of George Smiley's spies snooping into the deep dark secrets of the 1950's and 1960's, that's your call. But it won't help much going forward if you're hoping to revive the process.

I know how to make densitometer plots too. But I've also seen lovely DT prints where neither a densitometer was involved, nor masking. It's a highly malleable process by adjusting dye pH, bleaching, etc. The eye evaluating the result itself is a lot more important than "empirical methodology" involving endless numbers you can't seem to make sense of yourself.

DREW WILEY said:

In the course of that, I've developed all kinds of specialized masking tweaks AS NEEDED. But that doesn't mean they identically correspond to your imagined and historically incorrect notion involving a whole graduated series of progressive highlight masks. All kinds of improvisations occurred under special circumstances; some were no doubt invented on the fly. That does not mean they were routine by any means. And I could more easily tailor my own masking variations on demand, namely, using present films, not discontinued ones.

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In no way do I have a complete picture of what industry practices were either, as this is a legitimate question people should be asking. I have done extensive research into this, far more than what I'm presenting here. I have multiple sets of separation negatives from a few commercial DT labs and I must have spoken to more than 100 people in this field. I also made these myself and tested them and found the results converge to what one would expect to find.

If there were no significant specular highlights in an image, the specular mask might have been omitted. Or if there were no highlights and the mask would not serve any useful purpose it could be omitted as well. It depended on the decisions of the lab operators. The long range highlight mask was used when principle masks were used, which was every image. Could there be images that didn't use masking? Possibly, but that was not routinely done. Making color accurate reproductions of transparencies REQUIRED COLOR CORRECTION, for the reasons I have previously stated.

If Drew really believes he can make better masks and separations using current pictorial films, I would be interested in seeing the results and a reproducible method for doing so. So far I don't see any indication that he can. I am certainly not claiming to be the arbiter on color separation making, as there are still a number of things I don't know about.

DREW WILEY said:

Frankly, you're not just beating a dead horse, but a dead unicorn, by overcomplicating everything. And you're making assumptions about "standard industry practices" which were actually all over the map, involving not only numerous alternate routes, but even different sources of dyes and related materials.

If you choose to be one of George Smiley's spies snooping into the deep dark secrets of the 1950's and 1960's, that's your call. But it won't help much going forward if you're hoping to revive the process.

I know how to make densitometer plots too. But I've also seen lovely DT prints where neither a densitometer was involved, nor masking. It's a highly malleable process by adjusting dye pH, bleaching, etc. The eye evaluating the result itself is a lot more important than "empirical methodology" involving endless numbers you can't seem to make sense of yourself.

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That is your opinion. I'm fairly certain it what I'm claiming is true. Using other dyes was not common for commercial labs. There were other “dye transfer” type processes such as Printparency, which used different dyes, mordant, etc., but in the commercial Kodak Dye Transfer industry processes and procedures were remarkably similar, I have found.

I'm not sure what you mean by “endless numbers you can't seem to make sense of yourself.”? Making color pictures with numbers is vastly more effective than making them dependent on the subjective nature of the “on the fly” methods.

Pictures are visible; that's the whole point. And DT was noted for its great flexibility during the dying and rolling process, no statistician needed. But you've taken this to almost a religious belief it can all get worked out in advance using convoluted secrets, or should I say, largely mythical rigid dogmas. If you enjoy doing that, it's your perfect right. But I don't see it leading anywhere to the benefit of ongoing DT printing itself. You've painted yourself into a corner. And what you "have found", as you describe it, is awfully narrow-minded with respect to the scope of variations involved, even commercially during its heyday. What you appraise as "secrecy" might in fact be your high-horse attitude toward a number of the surviving veteran practitioners, who just don't want to Tango with you.

Practitioners like Bob Pace necessarily had to employ a lot of precise sequential steps, one after another, because he was involved in complex comps for the advertising industry, destined for offset printing as the final outcome. It was the Photoshop of the day, so to speak. But that's no longer the case. Nobody is going back to DT for commercial applications now done better by 10-year olds on their home computers. If there is a future for DT and analogous tactile processes, it's for artistic and decor purposes, or even hobby enjoyment if one is persistent enough.

And I sure as heck don't need to be lectured by you about the nature of color transparency reproduction - I specialized in it for 30 years. Yeah, Cibachrome is a simpler process than DT; but it's also more idiosyncratic and less flexible, and even more dependent on specialized masking. I've also mastered RA4 printing to an exceptionally high standard of reproduction, including starting with chrome originals. What was once the ugly duckling of the trade can now compete right down to the wire with DT, if someone is willing put as much TLC into it as I have.

Sure, I have numerous densitometer precedents and special protocols, and specialized equipment behind each of these routes. But that's just for sake of launching the booster rocket; what counts is the payload itself.

Gentlemen, please keep the debate constructive and congenial. In cases where lengthy deliberation doesn't bring resolution, consider the option to 'agree to disagree'.

Carnie Bob said:

Drew said- If one wants to attract new devotees to DT, they need to simplify the workflow and accessibility to needful ingredients as much as possible, not overcomplicate it with technical minutiae of only arcane interest.

This is a very important set of words. I have been working professionally for 50 years printing for others (including today) I have seen many different processes by many different printers and I must say the key to young workers is not to make it difficult for them but to give them a simple workflow to follow and as they get more and more interested they advance and make good prints. One sees this with the Colour Carbon Process , basically only a few can do it well and I know three of the best and in all cases the steps and methods are too advanced for beginners and people lose interest. This is why I like the gum over process, it can be done in the back yard with simple steps.
I worked at a Dye Transfer Lab in my past life and I remember the deer in the headlight syndrome considering doing this process.

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I believe a consistent supply of “dye transfer” (dye imbibition transfer) materials, and a hands on instruction would make the process much easier in introducing it to others. This would simplify many of the problems with using old film, synthesizing and formulating dyes, developers, etc. And yes probably using digitally created separation negatives would make the separation process a lot easier as well. I think there is value in optically separating a color transparency, but I tend to agree its a more advanced level.

There are a number of creative things one can do with it. The look of “dye transfers” are unique from any other process. If one were to fine tune their process, its possible to make prints that exceed the gamut of mainstream inkjet and type C processes. Dye prints are very archival and light stable as well.

Bob, what part of the Dye Transfer process did you work on? What lab was this? Were you trained at Kodak on Dye Transfer?

Archival "permanence" depends on the specific dyes involved. The Kodak sets were a compromise between easy transfer and retouching versus permanence versus hue purity. You can't have it all at once. And there can be little doubt that current Fuji RA papers have significantly better light tolerance under lengthy display than typical DT's, and that DT's fall well behind Ciba when it comes to dark storage life and resistance to atmospheric pollutants.

The repro problems of DT are well known. Poor highlight control (which would seem to warrant a whole new approach to making the matrix film itself), difficulty finding a pure permanent cyan process dye, not the sharpest printing media by any means, and the considerable amount of time, expense, and work space involved. Plenty of exposure to irritating acetic acid vapors (which is precisely why I avoided DT experiments during the Covid era, which happened to coincide with our terrible forest fire smoke issues in the State). Those are some of the "cons".

The "pros" also stand out : a highly tactile process appealing to certain printmakers. A particular purity to the colors difficult to achieve by other means, including the handling of neutrals. One can get hues saturated on opposite sides of the color wheel at the same time. Truly well-made DT prints are in the minority, but when you see one, you never forget it. In the hands of serious practitioner, it can put inkjet gamut to shame. The depth of blacks goes on and on, while inkjet blacks are discontinuous even in sheen. Dyes have a luminous transparency to them, while inks lies on the surface.

But I'd rate the potential of current C-prints more highly than inkjet too, when it comes to gamut and subtle hue distinctions. Most color problems with them aren't due to current RA4 print media itself, but due to the quirks of color neg films themselves.

IB Photochemistry said:

I believe a consistent supply of “dye transfer” (dye imbibition transfer) materials, and a hands on instruction would make the process much easier in introducing it to others. This would simplify many of the problems with using old film, synthesizing and formulating dyes, developers, etc. And yes probably using digitally created separation negatives would make the separation process a lot easier as well. I think there is value in optically separating a color transparency, but I tend to agree its a more advanced level.

There are a number of creative things one can do with it. The look of “dye transfers” are unique from any other process. If one were to fine tune their process, its possible to make prints that exceed the gamut of mainstream inkjet and type C processes. Dye prints are very archival and light stable as well.

Bob, what part of the Dye Transfer process did you work on? What lab was this? Were you trained at Kodak on Dye Transfer?

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Hi IB - I worked at BGM Colour Labs in Toronto, they were the last Dye Transfer Lab in the city , All the workers I met upon arrival had done Dye Transfer, but my job was photocomp and within a few months DTransfers were not done anymore. My friend John Bentley did them up until the early 90's.
I was never trained on the process, but all of the maskmaking we did for photocomp was derived from Dye Transfer. I was very competent in making masks using many substrates, we used micro modifiers to make choke and spread masks as well I was one of a few worldwide that worked on a Lile Camera system for photocomp , it took me 9 months of solid frustration to learn how to make masks and operate this bubble memory computer system that ran the Lile.

The DTransfer prints I have seen were very beautiful, I am not sure but I think they were part of the proofing process for advertising before Chromalins came out to the market place.

I started at photocollege in 1973/74 so a few things like DT were before the time I reached my peak.

Archival "permanence" depends on the specific dyes involved. The Kodak sets were a compromise between easy transfer and retouching versus permanence versus hue purity. You can't have it all at once. And there can be little doubt that current Fuji RA papers have significantly better light tolerance under lengthy display than typical DT's, and that DT's fall well behind Ciba when it comes to dark storage life and resistance to atmospheric pollutants.

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No, having looked at some archives on the team actually involved with creating the “Dye Transfer Color Process”, that is not entirely true. That is simply a wildly held belief that there was a compromise between transfer properties, hue purity, and retouching, and its only partially correct. The dyes they sold with the process (284-SPMP, Acid Red 58, Acid Blue 45) were in no way the best they had in any area. The other variable is cost of production, which Drew didn't mention. The Acid Red 58 (Brilliant Alizarin Light Red B (S)), and Acid Blue 45 (Erio Fast Cyanine) were desalted and further purified from the commercial dye powder. The aqueous solution of the dyes had better consistency, were replenishable, and were easier to work with than mixing powders.

And that is not correct about dye fading either. Dark storage of Kodak DT prints are estimated to last centuries. Ilfochrome/Ciba has a similar light fastness rating, possibly slightly less than DT, according to Wilhelm Research.

We have found dyes with much better fastness, hue, spectral properties, retouching capability, and heat stability. I can't say much here about this on this platform. Efforts to stop me have been unsuccessful.

The repro problems of DT are well known. Poor highlight control (which would seem to warrant a whole new approach to making the matrix film itself), difficulty finding a pure permanent cyan process dye, not the sharpest printing media by any means, and the considerable amount of time, expense, and work space involved. Plenty of exposure to irritating acetic acid vapors (which is precisely why I avoided DT experiments during the Covid era, which happened to coincide with our terrible forest fire smoke issues in the State). Those are some of the "cons".

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The shortcomings of DT are easily solvable. Again I have solved the problems with the Kodak dyes. I can't say much here about that except, I have synthesized a range of high fastness yellow dyes, and cyan dyes with more accurate hue and fastness. Organic mordants can give better sharpness, which are available that don't yellow over time.

Drew speaks of poor highlight control but bashes and attacks what I wrote about highlight masks, which he apparently never tried. Any high end commercial DT LAB USED MULTIPLE HIGHLIGHT MASKS in making the separation set. It was necessary for the commercial success of the process. Of course, Drew who claims to know everything about color separations of transparencies from his “30 years” of specialty in “transparency reproduction” should know all this. What he doesn’t know is that I CURRENTLY MAKE DT'S and the fault is not just the matrix film! The matrix film is not the weak point in the Kodak DT system.

The "pros" also stand out : a highly tactile process appealing to certain printmakers. A particular purity to the colors difficult to achieve by other means, including the handling of neutrals. One can get hues saturated on opposite sides of the color wheel at the same time. Truly well-made DT prints are in the minority, but when you see one, you never forget it. In the hands of serious practitioner, it can put inkjet gamut to shame. The depth of blacks goes on and on, while inkjet blacks are discontinuous even in sheen. Dyes have a luminous transparency to them, while inks lies on the surface.

But I'd rate the potential of current C-prints more highly than inkjet too, when it comes to gamut and subtle hue distinctions. Most color problems with them aren't due to current RA4 print media itself, but due to the quirks of color neg films themselves.

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I generally agree here.

How many "centuries" have you, or anyone else, actually been around to verify the wild guesstimate or BS marketing hype how many centuries this or that print medium will actually last? I actually have some background dealing with accelerated aging tests, and namely in pigments far more lightfast than any kind of photo dyes; and there are all kinds of loopholes in the testing technology itself, lot's of variables.

I have quantities of both Kodak dyes, indeed a little more convenient to work with due to matching pre-made buffer sets, as well as generic equivalents. None are equal to the pre-incorporated chromolytic Azo dyes of Cibachrome (which of course have certain color repro issues). Perhaps other potentially usable DT dyes are. Even claims about inkjet prints surviving in lovely shape for 200 years is marketing BS, since their inks are a complex mixture including susceptible dyes themselves. Quite a bit of study has gone into this in recent years. But extrapolating very brief test results decades and centuries down the line ... well, none of us are going to be around anyway, to verify this or that questionable claim.

You seem to be well behind the curve in terms of permanence studies. A lot of credit should be given to Wilhelm; but there are all kinds of known flaws in his methodology, which were well recognized as suspect in the pigment industry itself long before him. Aardenburg is way more up to date. I've done a lot of my own real-world testing myself over the past half century at least. Chromogenic prints have dramatically improved in permanence over that time. And Bettina in Germany claims to have developed a superior DT dye set in terms of light permanence, compared to the traditional Kodak version; so it's certainly possible. And I commend you if you think you've produced a superior set too; but commercializing it might not be so simple; you'd still need to find a realistic market.

The holy grail is really more in the realm of finding a process set of transparent nano pigments suitable for those kinds of processes, which is peripheral to DT discussion per se, but something I have been directly involved in sleuthing due to my insider trans-continental industry connections. I know less about dye technology per se. But testing methods are similar.

It's seems you're the only one who thinks the curve of matrix film is fine "as is". Plenty of others have complained about its "horrible toe", which is the apparently the real culprit in terms of complicated highlight repro cures. And if you can't find a far more simplified workaround to your alleged need for multiple highlight masks, there is no commercial future to darkroom style DT printing - all those multiples of sheet film are simply getting too expensive! Yes, curves can be re-profiled digitally, but that's a different story, needing its own kind of investment, with its own quirks.

What I should probably explain is that I too often think outside of the box. And a successful tweak of mine was to generate master chrome dupes with most of the contrast and hue corrections already factored into them. These were multi-purpose, so could either go straight to the next generation of interneg for sake of RA4 printing, or directly to Ciba enlargements, or toward black and white separation negs needing only supplemental masking relative to specific dye deficiencies, since other gamma issues can be controlled at the b&w sep stage itself. When all this is done via registered 8x10 film, there is virtually no qualitative loss even with third generation contacts, provided all the films in play are on dimensionally stable polyester base.

The sad part, is that by far the best candidate chrome sheet film for duplication purposes was only made for about a decade, and nothing comparable is available anymore. So there's no realistic way to take this approach anymore. But I did generate a quantity of them at the time, some of which have served me well going forward.

The question I'd raise about organic mordants in relation to DT receiving paper is the safety of it, health-wise. Eastman did all their mildly radioactive thorium mordant incorporation on industrial scale, with little risk to end users. But organic mordants have a bad reputation, and my question is whether they can be pre-incorporated, or would need to be user
applied to the paper? I fooled around with fixed-out silver gelatin paper, followed by aluminum plus uranyl nitrate mordant, which seemed to work well. The radioactivity of uranyl nitrate is so mild that it won't even fog a sheet of film placed directly under a bottle of it for a week, and allegedly won't even penetrate the skin. And one needs darn little of it for DT paper purposes. But that's certainly nowhere near as convenient as a pre-mordanted paper like Kodak and several other mfg sources once offered.

How many "centuries" have you, or anyone else, actually been around to verify the wild guesstimate or BS marketing hype how many centuries this or that print medium will actually last? I actually have some background dealing with accelerated aging tests, and namely in pigments far more lightfast than any kind of photo dyes; and there are all kinds of loopholes in the testing technology itself, lot's of variables.

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Usually pigments and dyes are tested using an AATCC standard. The testing usually involves exposing the substrate to a uniform irradiation of UV-VIS spectrum, usually from a Xenon arc lamp of known spectral output. The light exposure reciprocity of dyes and pigments are not always observed for some materials.

I have tested bright yellow dyes so stable there was no detectable fading and the print material started to break down itself. Organic molecules can be very photostable as well.

I have quantities of both Kodak dyes, indeed a little more convenient to work with due to matching pre-made buffer sets, as well as generic equivalents. None are equal to the pre-incorporated chromolytic Azo dyes of Cibachrome (which of course have certain color repro issues). Perhaps other potentially usable DT dyes are. Even claims about inkjet prints surviving in lovely shape for 200 years is marketing BS, since their inks are a complex mixture including susceptible dyes themselves. Quite a bit of study has gone into this in recent years. But extrapolating very brief test results decades and centuries down the line ... well, none of us are going to be around anyway, to verify this or that questionable claim.

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The Ilfochrome dyes don't necessarily have reproduction issues its the process itself that most likely does. Dye Bleach process, which does work well, does suffer from interlayer effects and other issues with the chemistry. Chromogenic processes will always have some amount of oxidized developer diffusion that effects adjacent layers, resulting in color desaturation and contamination. This can be seen at higher density of yellow and magenta dyes. The yellow becomes noticeably quite muddy. Dye IB processes don't have interlayer effects (aside from the color separation process) and can hold saturation, at higher densities.

Inkjet prints lasting 200-300 years on display is probably complete marketing BS. There is very little in the peer reviewed literature on inkjet print fading mechanisms and chemistry. The people who have invested in inkjet printers don't like to hear about this. A photograph conservationist told me once, he recommends if one wants to make an archival color photograph, a type C print would be much better than an inkjet, because we know more about how it will fade with time.

You seem to be well behind the curve in terms of permanence studies. A lot of credit should be given to Wilhelm; but there are all kinds of known flaws in his methodology, which were well recognized as suspect in the pigment industry itself long before him. Aardenburg is way more up to date. I've done a lot of my own real-world testing myself over the past half century at least. Chromogenic prints have dramatically improved in permanence over that time. And Bettina in Germany claims to have developed a superior DT dye set in terms of light permanence, compared to the traditional Kodak version; so it's certainly possible. And I commend you if you think you've produced a superior set too; but commercializing it might not be so simple; you'd still need to find a realistic market.

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I don't think Bettina Haneke has published any fading tests on their dyes. Looking at pictures on her instagram page, the cyan looks slightly greener than Kodak but darker, and the magenta is a little yellower than Acid Red 58. They were batching up large quantities of dyes in solution for running prints, so I don't think these are desalted dyes, and probably not replenishable.

The holy grail is really more in the realm of finding a process set of transparent nano pigments suitable for those kinds of processes, which is peripheral to DT discussion per se, but something I have been directly involved in sleuthing due to my insider trans-continental industry connections. I know less about dye technology per se. But testing methods are similar.

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What evidence do you have that transparent nano pigments would be light stable, and exhibit additivity and proportionality of absorptive density? Are there any peer reviewed papers on this subject? Nano particle materials are actually much more likely to be reactive, than on the macro scale. Transparent inorganic colorants exist. On the nano scale not only are there Raleigh scattering effects, but Mie scattering, and other interference phenomena near the wavelength of visible light. Quantum dots can be synthesized, and tuned for emission or absorption at specific wavelengths, but I don't see any evidence they would be superior to dyes in reflection print systems. If such materials exist it may be possible to simply add some sulfonic acid groups to the surface, so they can be taken up into gelatin matrices.

It's seems you're the only one who thinks the curve of matrix film is fine "as is". Plenty of others have complained about its "horrible toe", which is the apparently the real culprit in terms of complicated highlight repro cures. And if you can't find a far more simplified workaround to your alleged need for multiple highlight masks, there is no commercial future to darkroom style DT printing - all those multiples of sheet film are simply getting too expensive! Yes, curves can be re-profiled digitally, but that's a different story, needing its own kind of investment, with its own quirks.

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There were also trade secret compounds that could be added to the matrix tanning developer that could give a straighter curve, and a special method of matrix exposure. One such compound was 6-Nitrobenzimidazole, or derivatives of it. Flashing the matrix film can sharpen the toe as well. This was normally used with Kodak Pan Matrix 4149, using the sideband color of the main matrix color, for masking correction. There were many selfishly guarded Kodak trade secrets with the art and science of matrix making known to commercial DT labs.

Commercial labs typically over exposed the matrix film slightly, about 1/3 stop, and used a buffered rinse bath with Hexametaphosphate, to remove this excess density and make all three toe curves align. This was a technique apparently created by Kodak originally. The toe curves of Kodak dyes do not normally align well, and this is not due to the matrix film but the dyes themselves.

I'm not sure many professional labs complained about the matrix curve tow. And color negatives printed through interpositives didn't normally require highlight masks.

Many "amateurs" attempting to make DT's themselves would run into this 'horrible toe' and mention it. Most of them probably weren't even exposing their separation negatives correctly! They were probably exposing onto the toe of the separation film, thus exacerbating the appearance of the matrix toe! They have the transparency toe, the separation negative toe, and the matrix toe. This technique was omitted from the published literature, as far as I can find.

I did mention when exposing through a principle mask, one needs to increase the exposure for the mask transparency sandwich. The equation P = 10^(mask Dmax)*e, where P is the exposure factor, the mask Dmax is the Dmax of the principle mask, and e is a constant >= 1. So the separation negative exposure time is usually about 10-11 times that of the base exposure time, (as a direct separation).

IB Photochemistry said:

I don't think Bettina Haneke has published any fading tests on their dyes. Looking at pictures on her instagram page, the cyan looks slightly greener than Kodak but darker, and the magenta is a little yellower than Acid Red 58.

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You can make these subtle distinctions from an Instagram post?

I can't reply too much at the moment. Hopefully, someday I'll have an opportunity to see your own work in person. I have a lot of irons in the fire already.

I'm not a dye chemist, and you're unfamiliar with pigment R&D. Nano-pigment development has been ongoing by the largest coatings manufacturers' on earth for decades now. The market is enormous, particularly in certain auto and boat applications. The permanence is as good in terms of UV tolerance as the colors of the surface of Mars. But stretching that selection into the range of a full symmetrical set of process colors for sake of other industries is proving to be quite a challenge. And of course, pigment needs binder; and that itself is susceptible. So, no, the expensive translucent paint job of your low-rider Chevvvy is not going to last as long as the dust of Mars, or Artist's Point in Death Valley.

I've been in close contact with this for the past 40 years; and it's quite a fascinating study. These companies have a staggering investment in testing and quality control; but some of it is still hush-hush. It actually all began just across the Bay from me, where the largest optical coatings company on earth started playing around with essentialy scraping off the vacuum deposited particles and selling them as extremely stable pigments so fine that they were essentially transparent in a binder. My Supervisor at work lived nearby and invested in the venture, and within two years, sold off his stock and made enough to pay his kids entire college expenses. If he had held onto that stock another ten years, he would have been a multimillionaire. In the meantime, I was interacting with all kind of innovative uses of this new technology, which became highly profitable for our company. Since then, new methods of making nano pigments have sprung up worldwide, and the original big coating factory split up and sold off its different interests. I also had an inside connection to analogous R&D in the EU specifically for sake of visual purposes like art and the printing industry; but both of us have since retired, and I've lost track.

The best I've been able to do is come up with an alternate route of extremely finely ground regular pigments, pre-dispersed in industrial scale volume, which would be realistic for color carbon printing, for example - both more consistent in quality control, more affordable due to high volume manufacture, and probably more permanent than what is currently in use. Just a fun project to scratch an itch in my head; and I especially had the opportunity due to my industrial connections. I don't have time to take up carbon printing myself. Relatively transparent. As transparent and as tightly on target or hue pure as a typical DT dye set? - No. But a potential improvement for pigment printers. (Of no use in inkjet machines - there the overriding factor is those tiny nozzles and programmability; so compromises have to be made).

I'll try to more carefully read and digest your full post later in the day.

warden said:

You can make these subtle distinctions from an Instagram post?

Click to expand...

Doesn't seem too odd to me. This post in particular is relevant:
If you're used to working with these primaries a lot, you recognize very easily if someone uses somewhat different ones. Moreover, the Ig posts in question are pretty good, color-wise. Haneke seems to have quite good studio lighting. Figures, since she's working with color!

Get real ! Colors on an instagram post versus evaluating DT results in person? - that's laughable.

And that particular example, just posted, factors a lot of creative license in the use of dyes. DT can be manipulated all kinds of ways.

koraks said:

Doesn't seem too odd to me. This post in particular is relevant:
If you're used to working with these primaries a lot, you recognize very easily if someone uses somewhat different ones. Moreover, the Ig posts in question are pretty good, color-wise. Haneke seems to have quite good studio lighting. Figures, since she's working with color!

Click to expand...

I don’t know, if we say one person‘s green looks more cyan than Kodak green, but Kodak green is not in the same image for comparison, well I’m not sure how anyone would know because these are subjective colors displayed on a monitor that may or may not be calibrated, and we are relying upon color memory for that comparison which seems unreliable.

that’s a very cool Instagram page btw. I followed.

There is no "Kodak green". With DT, there are multiple points in the process to manipulate either the dyes themselves or the way the dyes interact, to produce an extremely wide gamut of options, or clean up seemingly contaminated colors.
Different Kodak films could produce quite different green repro challenges; especially the difference between Kodachrome and contemporaneous Ektachrome 64. Then Fujichrome arrived, and a whole new ballgame.

I won't go into how I successfully coped with this in Ciba printing; but I'm pretty sure my personal method was unique.

IB - I never implied nano-pigments would be of any value in DT printing. They don't operate on a pH mordanting principle, and they'd probably "poison" the matrix anyway. I was merely referring to them in relation to permanence and maybe someday in relation to true pigment printing. Although the manner of manufacturing has changed quite a bit since the 1980's, certain types have been around for a century now, and have been continuously tested under extreme outdoor circumstances the whole time - arctic climates, high altitude settings, hot humid tropics, decades of usage on wooden yachts all over the world. Yeah, the coatings themselves need to be layered back up on schedule; but the pigments themselves remain inert to UV.

Some of these products were awfully expensive, especially if one was taking into account a big wooden yacht or bridge, or major historical building reconstruction. There was one Frank Lloyd Wright building restoration where they used em inside and out on everything wooden - about a 6 million dollar project. I ran into that contractor not long ago. We used to interact quite a bit; but now, we're both retired. He had a wonderful portfolio book made of the project, and I begged him to submit it to a major publisher, but he never did.

I brought this up not to derail the conversation, but to indicate how different a time tested industrial approach to permanence is, versus brief-burst accelerated aging tests, which the coatings industries use too, but take with a grain of salt. I got real into it as an architectural color consultant, trying to prescribe color formulas that worked well together on synchronized pre-planned maintenance schedules.

You have to know not only how quickly certain mixes of pigments will fade, but fade at different rates in relation to another on different sides of a building, or angles of the sun. A whole fascinating world of its own, quite different from the behavior of transparent nano-pigments, where the lifespan is dictated by the weather resistance of the binder, and not by any hue shift in the pigments themselves.

The problem with inkjet print permanence is analogous - it all depends on the specific complex mix of ingredients in any given image, which does include dyes. Those different colorants fade at different rates. Aardenburg is an expert on that topic. At least with Cibachrome, the three primary dyes fade at around the same rate, so an overall color shift takes quite awhile to reach; ideally, you would want that characteristic with dye transfer dyes too.

warden said:

I don’t know, if we say one person‘s green looks more cyan than Kodak green, but Kodak green is not in the same image for comparison, well I’m not sure how anyone would know because these are subjective colors displayed on a monitor that may or may not be calibrated, and we are relying upon color memory for that comparison which seems unreliable.

Click to expand...

Not too long ago, Katayoun Dowlatsahi published a YT video of the Mme. Yevonde work she was printing. Part of that exercise involved figuring out what pigments would have been used back in the day. The video featured some very brief footage of some step tablets printed with the period-correct primaries. It would have been immediately apparent (as it was to me) to anyone working with modern pigments in carbon transfer that those primaries were 'off'. Of course, you generally can't draw any conclusions about where they land exactly on the color wheel, but if references are in view like neutral greys and skin colors, and if you're experienced in handling those primaries, it's often possible and even easy to spot if there's something significantly odd going on with them.

As to the DT primaries I see on that IG, I can immediately see they're totally different from the primaries you get in RA4 paper and the primaries I've worked with for carbon transfer.

Efke film itself wasn't a flop. The old EU factory itself was getting unsustainable in terms or maintenance issues. Their version of Matrix film was coated per Jim Browning's personal formulation, and he bought nearly all of it for personal use, and still has a substantial amount which he is almost daily using. The leftovers of the main production went up for sale through a film liquidator, and I bought some of that myself. In the meantime, most practitioners continued to use whatever Kodak supplies they still had. Since nearly all these people are getting way up there in age, it's doubtful they'll be interested in investing is some new kind of coating run.

The minor problem with the Efke matrix film is that they didn't double-filter the gelatin as Jim stipulated, so tiny specks
of that sometimes turn up and are visible in images at close inspection. He has a cure for that, but it's complicated.

As far as Bergger goes, they never made anything themselves. It was all sourced out. The wonderful Bergger 200 sheet film was made in the same plant as Forte, I believe, and previously marketed as Lotus 200; that plant closed down. Their black and white papers are made by Harman in the UK, and are still intermittently being coated.

I have heard there was more than one run of matrix film coated at Efke but it went to one client in Germany.

Apparently someone invested a large sum of money in a coating run of such a film in 2018-2020 period, at another plant in a European country. Its not a film for sale to the public. A small group of less than 10 people (who I won't identify on here) uses this exclusively. Not all of those are old retired people.

I do know that Kodak matrix film was very special in many ways. More research went into matrix film emulsions, than the dyes [as sold with the process], mordant, receiver blank, transfer chemistry, and developer, used in the process. The gelatin was extensively chemically modified and had certain properties.

The Efke matrix film will swell excessively after hot water etch as well as having small visible specs in the prints and in the dye bath. The matrix was formulated with the wrong type of gelatin and is rather soft. In addition, from my tests of this material the highlights were difficult to control. The film also has a "grainy" appearance being a near uniform mottle throughout the image areas of the film. Not just the large gelatin chunks. A coating expert has said this is caused by the subbing material becoming dissolved into the gelatin emulsion. I tested it by using a variation of the Wash-off Relief method.

Kodak published no sensitiometric data on Matrix 4150 or Pan Matrix 4149, or very much information at all on these films. I doubt any former Eastman Kodak chemists or engineers will comment on this, but I would be very interested if they can.