IIRC the Dignan Newsletter may have had the formulas for the original Cibachrome process.
Last edited by Gerald C Koch; 03-13-2013 at 09:21 AM. Click to view previous post history.
A rock pile ceases to be a rock pile the moment a single man contemplates it, bearing within him the image of a cathedral.
~Antoine de Saint-Exupery
If it comes down to it, a dye bleach process may be the only way we can home brew color reversal materials from scratch. The simpler dyes are quite available and the coatings are simple. I hand coated and then machine coated a simple example at EK and then did a single layer coating here at home about 2 years ago. The example was posted here IIRC in a long ago and forgotten thread on a similar topic to this one.
Also, there have been several posts here where people have mixed up a dye bleach solution that works. I have, but have not checked it with the Ilfochrome material itself.
But Ron ... if we are talking about anything resembling the quality of Ciba, and not just some stunt,
we are talking about an industrial chain indeed. Correct? Just acquiring the correct base material would
be a staggering investment in itself, and as I understand this, this was in fact the financial burden which broke the camel's back (along with distribution issues), and not just the advent of digital printing (inkjet is certainly not cheap compared to RA4 printing, for example, which was already around
parallel to Ciba for quite awhile). Polyester is inherently expensive, and Ciba used a special type. The gelatin was really fussy and they sometimes got bad batches. The material was fragile. But it just wouldn't look the same on a paper base (and they did offer a RC paper too). It's a helluva lot easier to
revive dye transfer.
You can get Yupo and other reflective plastic supports and other transparent supports for coating. Less stable but good dyes are on the market and many are food dyes or clothing dyes. Pick three. The coatings are straightforward. You can make a reversal material. Endura type papers or C41 films, now that is hard!!! I've done both.
Of course it will not be Ilfochrome quality, but it will work. It will take dedication and a lot of hard work to get something usable. It may take years. But, it can be done. OTOH, as I said, C41 and RA4 materials are just about impossible for the home hobbyist.
A dye bleach solution can also be made to work with current materials with dedication and a lot of paper to burn, and a home brew coating will be usable but no Ilfochrome. In that case, you tailor your dye bleach solution to the new coating you are designing.
Technically, Ciba wasn't a reversal process at all, but a direct positive process. Very high quality azo dyes are still available - no need for food coloring. As you already proably know, I'm one of the folks
who acquired commercial dyes for dye transfer work which are nearly indistinguishable from Kodak brand dyes. I have full sets of both. But what I'm really interested in are further developments in
nano-pigments, which would revolutionize this entire subject.
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Well, getting high quality azo dyes is a problem, and the Dye Transfer dyes do not work with dye bleach.
I get your point about the process, but you must know that in the trade, direct reversal refers to the emulsion. So, there are direct reversal emulsions.
Well if it's that (relatively) simple that someone COULD do it at home, could one of the smaller black and white companies like Adox or Foma produce such a material and the chemistry? Or even just formulas for the chemistry? I think developer and fixer are just standard B&W items so really just a bleach or even readily mixed formula for bleach.
Roger, yes it can be done. However, the dye stability and color quality may be a problem. It surely will not match Ilfochrome. It will most likely produce a usable but drab image. It will certainly not have the image stability of Ilfochrome.
But, one works with the tools at hand.
The chemistry isn't the issue, Roger. You can get an idea right off the MSDS sheets. The developer was just a tweak and substitions were in fact jerrrigged or second-party marketed. The bleach, mainly sulfuric acid with additives, the fix, ordinary non-hardening fixer. The health effects of the bleach were
serious at a lab scale, and very corrosive to equip and plumbing. To a small batch drum user, this was a minor problem. The paper as we know it was tricky and expensive to mfg. Nobody in their right mind
is going to invest in something like that again. Besides, chrome film is getting scarcer; and although
stunning images could be generated onto Ciba using laser printers, it was never particularly common
to do so, and Fuji Supergloss is way easier and more affordable to work with. Ciba paper ages quickly
once opened, so the color balance shifts. And with regard to optical printing, you need polyester based
chromes to start with, or keeping the masks in register is hell. And we've just lost such films. So really,
it is the end of an era in terms of anything commercially viable. I'm filling the void with optically-printed
Supergloss, and somewhere along the learning curve regarding appropriate masking options. Should be
an interesting year ahead of various triumphs and inevitable bellyflops, at least as far as interneg work
is concerned. Basic color neg printing with this material is the same as with any other RA4 paper.