Dye transfer is a photographic process usually reserved for color archival work and high-quality copy. For the large part of the 20th century, it remained the color gold standard due to its high saturation, contrast, detail, density, and fade-resistance. Technicolor was originally a dye transfer process. Kodak discontinued all chemicals and films necessary for the process in 1995, but some dedicated folks have continued to slog on. Technicolor was reintroduced in 2001, but discontinued again in 2003.
So what the hell is dye transfer about?
Creating dye transfer works is an extremely time-consuming process. The source (color transparency) is exposed through red, green, and blue filters to make black-and-white negative separations. These separations are then used to expose gelatin-coated matrices. Each matrix sheet is exposed and developed, causing the exposed gelatin to harden. Unexposed gelatin is rinsed away, leaving a relief image. The matrices are soaked in acid dyes, and the remaining (negative) gelatin absorbs the dye, which is then transferred to the final print. The printing stage requires manual registration of the three matrix dye carriers, as shown in the above image.
The matrices are reusable, provided they are treated gently, so sets of dye transfer prints may be made from a single matrix set.
At each stage, the image may be tweaked in what I have heard described as a "manual photoshop" method. (I believe the irony was intended.) Areas may be dodged / burned during the first step of creating the separations, or during matrix exposure. The dyeing chemistry may be altered to adjust response curves, saturation, or highlights for the individual separations.
I saw my first dye transfer in person at a world science fiction convention about a month ago. I sat in on a panel entitled "Someday My Prints Will Come" which I thought would cover different printing techniques that I was unfamiliar with, like serigraphs, lithographs, and yes, dye transfers, but instead everybody talked about scanning issues, inkjet printers, digital workflow, and what constituted a limited edition. (HINT, it's limited!)
There was a creaky gnome-like hippie named Ctein on the panel who caused my sympathetic ur-geek strings to resonate. He and another panelist were docenting a tour through the art show at the convention later that afternoon, and I figured it would be interesting to tag along and hear what they had to say. While passing by booths, Ctein waved his hand towards one, saying something dismissive, and continued on.
Something about that booth caught my eye, though, as most booths contained paintings, and not photos. This booth had photos of things like reactor cooling towers, and, hey that's mt. st. helens, and while I was examining some lava rocks, the print density started to hit me. It was like I was viewing some sort of mounted transparencies, the contrast was so high. Oh, wow, these are Ctein's? What the hell is he doing to print these things? So I asked him. Dye transfer was the answer.
Apparently Ctein isn't alone in his obsession with this obsolete color printing process.
Luke Powell has made series of dye transfer prints of pictures taken from far corners of the world. James Browning has even gone so far as to create his own emulsion coaters to create gelatin matrix sheets, and his own dye formulations so he can keep dye transfer alive.
I'd love to try it myself sometime, but staring at the stacks of unscanned and unprinted negatives on my desk, I don't think it'll happen anytime soon.