Color Dye-Transfer Prints for the Modern Hobbyist - *Imbibition for For the People!*
HISTORY of the PROCESS
In 1994 Kodak discontinued the "Kodak Dye-Transfer Process". Since that time, only those who have hoarded those materials or have been enterprising enough to manufacture their own silver-halide matrix films (Jim Browning) have been able to make dye-transfer prints.
However, this is a curious & unfortunate state of affairs! The earliest dye-transfer (or dye imbibition) prints were made by exploiting the same mechanism that modern day carbon & gum printers use; the ability of potassium or ammonium dichromate to harden gelatin upon exposure to UV light.
The 2 most common ways to a make a dye-imbibition print both rely upon a gelatin matrix.
In recent times (Kodak) the preferred method was with a silver-halide emulsion on a clear base. A negative is exposed through the base and developed in a tanning developer which hardens the gelatin in situ with the developed silver. This is then "etched" in hot water, which removes the gelatin that remains untanned (soluble) to reveal a relief image that clings to the base. This gelatin relief consists of varying depths that correspond directly the shadow density in the photograph.
The other method is very similar, but instead of using a silver-halide emulsion, a gelatin layer is sensitized with dichromates and exposed (again, through the base) under a negative and etched in hot water. It is this variable gelatin relief that absorbs dye to varying degrees, thus continuous tone is possible.
An obvious difference between these 2 methods is that the silver-halide emulsion can be exposed under an enlarger whereas the DCG (dichromated gelatin) requires an enlarged negative for contact printing. This is one important reason for the success of the silver-halide method.
However, the use of DCG matrices has many precedents, most notably the Pinatype process; outlined here in this British Journal of Photography article from 1907. However, the first application of this property that gelatin will imbibe & transfer a dye was disclosed by Charles Cros, a Frenchman, who called it the Hydrotype process in the late 1800's. Another process was Jos Pe. It should be noted that the Pinatype uses a slightly different type of matrix (one that is not etched = planographic, as opposed to relief) and correspondingly uses a different class of dyes and is exposed under positives, interestingly enough. No need to go into this in depth at the moment however....
So, to make a dye-transfer print, a relief matrix is soaked in a bath of an acid-dye, the dye imbibes (or migrates) into the gelatin relief image and this is then rolled into contact with a sheet of receiving paper. The dye transfers from the matrix to the receiving paper.
If 3 matrices are prepared from color separation negatives, and dyed in the appropriate secondary dye colors (CMY), and finally transferred in register to the receiving paper, a full color image is formed. This is the process in a nutshell.
Although my work on this technique is far from complete, I want to at least disclose and compile all the information so far gathered, so that other people who are interested may join the effort.
- PREPARING THE MATRICES
First, the modern worker needs a suitable clear support. This is found in Photo Formulary's Estar Melinex (mispelled on their website as 'melenex'). This is a thin, clear support that is subbed to accept emulsions. This subbing cannot imbibe any dye itself, which is ideal becaue otherwise you will get stained highlights. Although I have not tested any other materials, I'm curious what else might be suitable. Overhead transparency paper perhaps? Whatever the substrate is, it must be treated so that it "grabs" the gelatin, otherwise it will easily peel off. Search "corona discharge" for more on this, or APUG member hrst's work with substrates. Fortunately, there is an existing product at the moment.
The melinex scratches easily, and care should be taken to keep it as unblemished as possible. Vaseline or some kind silicon oil (PE) might be able to hide the scratches when it comes time for exposure (remember, we're exposing through the base).
As a side note, another option would be to do a "carbon transfer" of the clear relief image (or pigmented relief image for that matter) and this could become the matrix. This would eliminate the need for exposing through the base and a special substrate for the matrix.
2nd, you must coat the melinex with a gelatin layer. This is effectively no different than pouring carbon tissues (sans pigment). I have chosen 6% gelatin with 1% sorbitol, though there is nothing yet to suggest that this is superior to any other concentration, and not enough testing has been done to see what effect the gelatin composition will have upon the matrix characteristics. This gelatin solution pours nicely and makes a thin coating; this has been my only criteria so far. Each worker will probaly find their preferred way to achieve this, just like in carbon pouring.
3rd, the matrix blank must be sensitized. Having very little experience with this personally, I can only say that it will be necessary to have the back surface clean of any splotches before exposure, and also the deepest layers of the gelatin must be sensitized. It has been suggested (Vaughn) that this is not really a concern.
Fortunately, the rigid densitometric requirements of traditional dye-transfer printing can likely be thrown out the window when using DCG matrices. Traditional AgX matrix films had but one contrast grade, necessitating strict control of contrast in the sep negs. Thanks to the contrast control available from dichromate sensitization, considerable leaway should be had.
Chalk one up for DCG-imbibition!
4th, UV exposure under negatives. The ins & outs of making color separations are best left alone in this discussion, but tri-color gum printers will probably find their negatives excellent for preliminary testing. I am exploring the route of making enlarged negatives on mammography x-ray film (with an intermediate panchromatic step), which so far has proved promising.
5th, etching in hot (120°F) water, just like carbon. Due to the nature of the hardening by dichromates, control should be exercised to ensure consistency. This difficulty is eloquently (if not somewhat discouragingly) described in this post.
6th, at this point, one should probably clear (sodium sulfite?) the matrices and perhaps harden them. However, I can't recommend anything at the moment. Some hardeners, like chrome alum, might act unfavorably as mordants in the matrix, where we don't want them. Will advise.
As it stands now, obtaining appropriate dyes is the single biggest roadblock. Recently, a couple boxes of Kodak dyes came through eBay and sold for over $100 a pop. Not a sustainable solution.
Jim Browning has listed the following dyes in his PDF for Dye Transfer Materials: Acid Blue 45 (or 25; bluer and transfers slower), Acid Red 80 (or 289*), Acid Yellow 11 (or 23*) [*brighter colors at the expense of light-fastness].
J.S. Friedman, author of the monumental "History of Color Photography", lists a number of textile dyes that may be suitable for the process and I would encourage people to explore that route. Although the color demands might not be perfectly met, textile dyes are easily obtainable and might be perfectly satisfactory for the imaginative printer. These textile dyes, known as "Acid Fast", will likely work and are available very cheaply. I suspect that their light-fastness is good if they are well regarded by textile folks.
Many sellers on eBay have large quantities of dyes, usually being liquidated from old labs, etc. All dyes have multiple names, so consult a book like Sigma-Aldrich's Handbook of Stains, Dyes & Indicators (easily available from most University libraries) to find out alternate names, chemical information, lightfastness and color quality.
The best option might be to find a manufacturer that offers samples of their dyes. A sample is likely to be sufficient for many, many prints, or alternatively, you might wish to see what their minimum quantity is.
When all is said and done, availability of dyes will be the key to truly making modern-day dye-transfer a reality. I am fortunate to have a wide variety of old dyes given to me by a chemist who researches dye-transfer, in addition to synthesizing his own dyes. So, perhaps there is hope that in the future we can provide better options in this regard. In the meantime, I will use these dyes to test my materials and will be simultaneously exploring alternative dye options, such as textile dyes.
A word about dyes: acid dyes happen to have an affinity for gelatin, that is, they will stain it. This affinity is increased with lower pH (more acid), and thus the receiving paper is soaked in an acid solution to encourage the dyes to leave the matrix and transfer more completely. Logically enough, to clear the matrix after transferring, a dilute ammonia solution will liberate the dye from the gelatin. A matrix can be reused many times, another reason why this process was so successful (ultimately superceding carbro in the industry).
There have been other methods to make prints with different classes of dyes like Pinatype above, which used "Pina" dyes... a.k.a. a proprietary dye (though Friedman lists the probable candidates). Also, there have been methods to use basic dyes, which are exceptionally brilliant & pure, but are very quick to fade. Since these dyes react differently with gelatin, different materials & methods are required. See Friedman if interesetd.
But acid dyes are the preferred class because they are quite good in color, and are the most permament of dyes. Other dyes that will act in the same manner as acid dyes are "direct" and "reactive" dyes, though I am far from an expert on these matters.
For an excellent paper on the requirements & testing of dyes, please follow these links -> Part 1, Part 2, Part 3, to Dyes For Imbibition Printing by Colton & Thronson.
Any information on dye-transfer printing, such as that given by Jim Browning, or Ctein, or Kodak's publication E-80 will give you a solid idea of what is necessary for transferring the print, as this function is independant of the kind of matrix used. At the moment, this is my least studied area of the process so I'd hate to give misinformation. It is however, pretty straight forward.
Basically you soak the matrices in their respective dye baths until they reach equilibrium (that is, the time it takes to absorb all the dye that they can hold). Then, you transfer them to a dilute acetic acid bath of about 2%. This rinses the excess dye off. At this point, in the acid bath, the dye will not exit the relief, and if the 3 matrices are not registered yet, they can be visually aligned in this bath and punched. The color image will be visible at this point.
Each matrix is then rolled onto the receiving paper, one after the other. The time that it takes for the dye to exit the matrix and migrate to the receiver paper will be a function of the dye, and will likely vary (as it did in the Kodak process). Standard practice is to transfer each color twice.
Another important aspect is the receiving paper itself and the pre-treatment bath. Kodak supplied a pre-bath for the receiving paper, but at the moment I couldn't tell you exactly what is in it. It stands to reason that it would be an acidic bath, and indeed, a sloshing of vinegar (not very scientific, nor ideally probably) helped a down & dirty test succeed while testing with a food dye. See here.
So as you can see, considerable room for experimentation is present. For initial testing, fixed out photo paper will be more than sufficient and actually the hardeners present in the emulsion, or from some fixers, will act as mordants in their own right.
An idealized receiving paper will have a dedicated mordant. F.E. Ives first suggested this method in U.S. patent #1,121,187, 'Photographic Printing Process', from December 15th, 1914. Basically, the mordant increases the paper's affinity to hold onto the dye (from the French word mordere, "to bite").
F.E. Ives has many earlier patents describing the use of DCG matrices for imbibition printing. Friedman doesn't spend much ink in discussing dye-transfer matrices of this type, instead simply saying that F.E. Ive's patents on the subject can be considered the authoritative text. Indeed, I would recommend anyone interested to seek them out, and I'll be more than happy to include the patent #'s. (p.s. They are listed in Friedman, and that book is available on Google books).
So as you can see, the work is just beginning. But all the information is out there and nothing is beyond the scope of the hobbyist. It just isn't formalized as of yet, so there is a lot of original & novel work that must be done before we can start "spreading the gospel" and telling people exactly how to do it.
I hope this will encourage a few people to give it a go, and remember that if tri-color seems daunting, there's certainly nothing wrong with monochrome prints. That would greatly expand the list of possible dyes for the process.
More to come in the future...
- Chris Holmquist, holmburgers, 2011 -
Last edited by holmburgers; 05-25-2011 at 05:20 PM. Click to view previous post history.
Dewey, it sounds as if the "special" quality of the Pan Matrix film was in its convenience to get a positive tanned matrix relief from a C41 image in one step. Is the spectral sensitivity of the emulsion any different than other modern pan emulsions like TMax 100?
Yes, a direct-from-neg solution, convenience and accessibility for advanced darkroom users were the point of the product. Plus, it produced really beautiful dyes. Maybe it was the directness of the process or the greater range of color negs, but they could look really spectacular.
I don't recall that it was anything unusual about its sensitivity, but exposures through the blue filter could run quite long.
Of course, this product is long gone except for any that's been hoarded in a freezer. And despite the respect I have for anyone attempting to revise the dye transfer process, I think that the challenges are pretty substantial. I hope the payoff is worth it.
If we forget about analog separation negatives the process really isn't all that challenging; not much different than carbon, especially in the making of the materials.
My desire is not necessarily to reproduce the fidelity, color, saturation & rendering of a professional made dye-transfer print (yet). I figure if people are getting enjoyment & making attractive prints from tri-color gum, which is far from technically perfect reproduction, then spitting images of reality from this imbibition scheme need not be the goal.
As time passes and ideally more people jump on the bandwagon, each step will become more refined and the collective wisdom will grow, with new ideas & contributions springing forth. I think that carbon & dye-imbibition are poised to potentially be the only "analog" options for printing color photos in the future, and I would love to see a renaissance. The beautiful thing is that it can appeal to digital shooters just as equally.. and no darkroom needed!
Check out this print... http://gary.saretzky.com/photohistor...sky/index.html The scan is low quality, but this is an imbibition print made by F.E. Ives at the request of Elias Goldensky, using his tripack film and a Hi-Cro camera in 1916 (information courtesy of Gary Saretzky). I see a lot of potential from this print.
If you are the big tree, we are the small axe
I understand your point completely. I would love to experiment with tricolor carbon from large format, but I'm concerned that I would a) never see my family b) go broke c) spend all my time in the darkroom and not shooting.
Likewise, I could imagine shooting with my iphone and printing small Epsons with the same satisfaction.
The darkroom is definitely addictive. It's a tragedy that the films once available for the intermediate steps are mostly gone. Pan masking, pan highlight, separation negative film, super XX are all gone. For me this seems like a closed (maybe slammed shut) door, but to your credit, you seam to see it as a puzzle.
On the bright side... you're probably getting some killer deals on used gear. Every now and then I look at darkroom stuff on Ebay (darkroom porn) and lust for a Leitz Focomat IIc or a Durst 5x7 for a crazy low price.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
This extensive list includes a number of dyes that are suitable for the dye-imbibition process.
I haven't done any checking yet, or specifically looked at the product offerings of any companies, but it's entirely possible that there are a handful of companies in the U.S. that will sell these (3 listed below) or better yet send you a sample of the dye for free. I had great luck obtaining pigment samples for color-carbon in this way. The amount that you receive as a sample will probably be enough to make many, many prints.
http://www.organicdye.com/ - http://www.pylamdyes.com/ - http://www.classicdye.com/
- Acid Blue 45, EK cyan dye for Kodak Dye Transfer Process. Blue not really cyan in color.
- Toluidine Blue I - CAS: 3209-30-1,CI# 63340, lightfast bright cyan hue, note: this is NOT "Toluidine Blue O" or Basic Blue 17.
- Acid Blue 277 - high lightfastness, much bluer that CI Acid Blue 45 transfers well. High mobility.
- Direct Blue 87 - I thought this was a bit poisonous but it was mentioned in a publication and it has a good cyan color.
- Reactive Blue 5 - one of the Morey Bard's dyes. Not good spectral purity; similar to Acid Blue 45.
- Reactive Blue 19 - nearly the same color as CI Acid Blue 45, higher light fastness. From Morey Bard of B.E.E.
- Acid Blue 258, TECTILON BLUE 6G - more green and saturated than Acid Blue 45. Doesn't transfer very well.
- Tracer RB Blue - Possibly CI Acid Blue 88 or 80
- Acid Red 58 - same dye that was used in Kodak Magenta. Possibly available from Crescent Chemical Co. Inc.
- Acid Red 80 - slightly yellower than Acid Red 58, less gelatin absorption.
- Acid Red 131 - reddish magenta color.
- Acid Red 167
- Acid Red 249, Orco Milling Brilliant Red B - bright magenta color
- Acid Red 257
- Acid Red 264 - Dr. Jay Patterson claims is good a magenta.
- Acid Red 274 - bright color, good spectral purity.
- Acid Red 388 - bright color, good spectral purity.
- Direct Red 83 - reddish magenta color.
- Direct Red 227 - good magenta color.
- Direct Red 243 - reddish magenta color.
- Direct Red 75 - similar to Direct Violet 62, good for transparencies.
- Reactive Red 49 - dark magenta.
- Reactive Red 66 - similar color to Acid Red 58 but yellower.
- Ramazol Brilliant Red R.F.C. (Hoechst) - possibly CI Reactive Red 35. Bright color, slight permanent stain.
- Hostalen Red 4 B.N. (Hoechst) - Reactive dye unknown CI name
- Acid Violet 7
- Direct Violet 47 - similar to Direct Violet 62.
- Acid Yellow 17 - good light fastness
- Acid Yellow 19 - bright yellow color and spectral curve but not heat stable
- Acid Yellow 34 - good yellow color, good spectral curve, high light fastness
- Acid Yellow 42 - good yellow color
- Acid Yellow 151 - metal complex might be slightly poisonous. Has good saturation.
- Acid Yellow 169 - greenish yellow.
- Acid Yellow 174 - high light fastness, good spectral curve.
- Acid Yellow 200 - good yellow color and spectral curve.
- Direct Yellow 11
- Direct Yellow 12
- Direct Yellow 14
- Direct Yellow 44
- Direct Yellow 50
- Direct Yellow 86 - medium yellow.
- Direct Yellow 106 - reddish yellow.
- Direct Yellow 142 - has long absorption tail, but has good color.
- Reactive Yellow 15
- Reactive Yellow 24
- Reactive Yellow 37 - bright yellow might have leak in spectrum.
- Reactive Yellow 86 - greenish color; low saturation narrow peak.
- Direct Orange 37 - can be used in mixture with compatible dye.
- Direct Orange 26 - can be used in mixture with compatible dye.
- Reactive Orange 86 - can make a good yellow for transparency use.
- Basilin Yellow E.3R. (Hoechst)
- Acid Green 25 - medium bluish green dye
- Acid Green 41 - bright bluish green dye. Not compatible with most mixtures of Anthraquinone dyes including Acid Blue 45.
- Procion Black SP-4 - I haven't located the CI number. Good fastness, fairly neutral on Kodak DT paper.
- Direct Black 38
This should be enough to get anyone started, eh?!
Also, for anyone that wants a "plug & play" solution, investigating the Procion Reactive Dyes would be a good place to start. These are readily available.
Lastly, it should be noted that I cannot take credit for this extensive list, or the hard work that went into creating it. That goes to Michael Garelick; a passionate and uncompromising researcher into this process.
If you are the big tree, we are the small axe
Wow.You're pretty serious about this.
I was contacted by Michael. He's got a good handle on this.
Is this info being compiled in any sort of common area? It would be good to start a DT group site to warehouse all this data. Has anyone contacted Guy Stricherz? He was the last man standing in NYC with his lab CVI, which made dyes for big shot art photographers. He would have the freshest memory of masking techniques, developing times, etc.
I think Chris's article here is a first stab at getting things compiled.
Originally Posted by Dewey2
I think he's done a bang up job.
In fact, I make a motion that we rename it Holmbergurs Dye Transfer method.
I'm serious about it in the sense that I really enjoy doing it, reading about it and ultimately thinking about a photographic system and all its complexities. Since graduating college it's become my sole "academic" pursuit, and the support of people I've met online has been great. I've been pointed in the right direction many times.
I'm also lucky to have a relatively relaxed job... If only I could get paid for this!
Mike G. really latched onto my idea to produce DCG matrices and has elevated the project orders of magnitude.
Guy Stricherz sounds like a good man to get in touch with as well; there are undoubtedly countless "tricks of the trade" that lie with only a handful of people.
You know, the funny thing is.. I've maybe seen 5 dye-transfer prints with my own eyes since undertaking this, but, when reading I have a most vivid imagination.
If you are the big tree, we are the small axe
It's great that you're doing this. And I agree that it's a bang-up job.
I hope that you get to see more dyes. They all share common elements that make them beautiful, but it's interesting that the quality varies wildly.
A lot of Elliot Porter's dyes are rather mediocre - despite his strong identity with the process. And William Eggleston is all over the place. Some are very nice, while others have all the subtlety of a color Xerox.
I still remember being overwhelmed by Bruce Davidson's Subway show of oversized dyes. And Mappelthorpe's flowers were absolutely, meticulously flawless. These were a pet project of Frank Tartaro's. I made seps on most of these and Frank was rejecting whole sets of seps for a microscopic dust spot.
I bought some Harold Edgerton dyes a few years back (bullets going through apples and cards, etc.) and I'm tortured every time I look at them and see dirty highlights and plugged shadows. I wonder if sound engineers have trouble enjoying music?
Amazing you mentioned those 1st two; the only prints I have seeen were one of Eggelston's shots of Graceland (National Portrait Gallery) and several of Porter's prints of his 35mm work (Amon Carter Museum). The latter were surprisingly uninspriring.
That's great though, that means I haven't seen the best.
Always loved Edgerton...
If you are the big tree, we are the small axe