I'm very glad that there are more dye transfer processes out there. I have seen some of Jim Brownings prints at his web site, but I can't judge their full quality unless I see them in the flesh. The Cteins are just beautiful and perhaps I will figure out a way to photograph parts of them which illustrates the rich detail and unique colors they exhibit.
The Kodak dye transfer system I consider unsurpassed--IMHO--partly because its inventor, Louis Condax, used innovations that other processes lack; and partly because its materials are among the finest and are not used in other processes. Ctein I consider a master of the process, but alas he has run out of raw materials. Kodak DT images should last hundreds of years if stored in the dark, however I have heard that it is not perfectly light stable, which is a disappointment. I'm taking no chances and illuminate my examples only when I am showing them.
Condax developed mylar supports for the relief matrices which allow for reliable registration; and he also invented a more efficient masking system which produces an extra set of matrices to transfer a much greater range of dye tones to the print. This produces probably the deepest gamma and the broadest range of hues available in color photography. Of course Kodax DT prints used thorium as a mordant for the dyes. This is a radioactive element and a Haz Mat license is required to use it. Kodak dedicated a wooden coating machine to apply the thorium nitrate to the blank print paper and after Kodak stopped manufacturing DT supplies the company burned this wooden machine so it could not contaminate anything. Some processes out there might still use thorium.
Condax invented a way of coating the thorium on the paper to give a more detailed image, US pat 2,952,566, and this kind of print paper was probably the finest in the world for DT. Using panchromatic matrix stock removes another generation of duplication from the final image; plus it fits in to Condax's masking system. I have indicated in an earlier post that Ctein has a technique which exploits this panchromatic character.
Unlike Technicolor dye transfer the Kodak process did not require color timing. In Technicolor the matrix had to be at a particular temperature, the dye at a specific ph and the transfer take exactly the right amount of time or the print would be too dark or too light in that color. In the Kodak system temperature and ph are controlled only loosely, but the matrix can be in contact with the final print for a short or a long time. Once the matrix is applied to the print then the dye solution reaches an equilibrium and no more dye will transfer no matter how long the matrix remains in contact with the print. A set of matrices will deliver the same color values repeatedly. We may never see the like again in our lifetimes.