This sounds like a half-understood muddle between various extended techniques used when chromogenic printing on current higher contrast papers, and/ or trying to force a troublesome neg into dye transfer without really understanding either. A properly exposed (this is the key aspect here) colour neg is inherently masked for colour and contrast control (with limitations on misuse for maintaining sufficiently accurate colour - as you should know if you have done even the bare minimum of colour critical work with colour neg, for that matter, had to get misused CN film to produce a good print). Getting the density equalised sufficiently on an overexposed sky is not the matter at hand when discussing the baseline fundamentals of the process.
No, Lachlan you have the misunderstanding. All chromogenic color materials, E6 films, RA-4 papers, and color reversal papers, have internal color masking for correction of their OWN DYES. Lachlan is making a muddle of the dyes used in the NEGATIVE FILM and the DYES USED IN THE PAPER. I think we can both agree these are not the same type of dyes?
Different dyes require a different type of masking. Dye Transfer dyes do not have the same spectral characteristics of the coupler produced dyes in color negative film. If the dye densities from the color negative are transferred to a matrix film, they will have insufficient color correction. Masking correction is required when using any real set of dyes. In fact Kodak acknowledged this a few times, for example, in a publication titled
Three Color Separation Prints from Color Negatives using Resisto Rapid Pan Paper, where red and green light correction masks could be used with this process.
There were no great secrets in the Pan Matrix emulsion. Its lack of sophistication in terms of emulsion technology is what killed it. It was early 1950s in terms of emulsion fundamentals.
How much research have you done Lachlan into matrix film formulations? Pan Matrix 4149 was a 1960's emulsion, it had another designation before that. Kodak decided to discontinue it a few years before Dye Transfer was discontinued; it had nothing to do with “lack of sophistication”.
Do you still think this was just unhardened Super XX pan mixed with dye? Its not, and we know that because of its far red sensitivity. It also had a light scattering medium in the emulsion designed to scatter the pre-flash exposure. Similar emulsions used a mixture of carbon black and Titanium Dioxide pigment, I have found from my research.
I also happen to know people who taught dye transfer (and other colour separators from elsewhere in graphic arts) at a further/ higher education level in the UK from the 1960s onwards as part of advanced colour printing techniques, and the clear opinion I have heard was to the effect of 'Pan Matrix was much easier to work with, compared to working from transparencies', not lots of lengthy claims about needing complex pre-flash etc.
Kodak customers knew about these other secret techniques everyone else didn't know about. The flash procedures were a selfishly guarded trade secret, that
does not appear in any published literature on Dye Transfer. Most of the industry used color transparencies not color negatives, and it often worked better to separate the color negative and print it using matrix film, because multiple images were often added and that gave more control over the process. Frog Prince, CVI, Tartaro, etc. almost never worked with Pan Matrix. Besides the flash procedure various tweaks were used in the tanning developer for each matrix individually, from what I understand. I think Tartaro Color Lab simply made a transparency from a color negative then separated it like any other transparency, others made interpositves and masks.
That was not my point. A proper coating blade as discussed by Ron Mowrey is capable of delivering coatings of very high quality. The problem is emulsion scaling. The volumes involved in the open source JB emulsion are very much greater (and will by all accounts readily scale up to industrial scale) than you would want to make for initial coating experiments, but if you scale down (from 5L to 500ml, for example), you may run into non-linearity (Debye and Hückel). It's a (potentially wasteful) headache rather than a complete stoppage, and would be solved very readily were a company like Adox or Foma to make a batch of decent size and bottle it in 1L quantities. It would then be much more easily stored cold, then the portions needed for coating a given set (or sets) of matrices could be used, rather than having to rejig the emulsion to enable sub 1L makes (making a 5L batch is getting industrial, fast).
Again Lachlan how much do you know about matrix film? Matrix was coated to very tight tolerances by Kodak. These are your opinions not facts. From my research the Browning emulsion was never very good. I spoke with Dr. Dick Goldberg, who designed the Printparency matrix film, and he said the Browning formula wasn't a very good film. Those who want to know why can research his work. The Browning film was basically slopped together using a simple Bromoiodide emulsion. It doesn't use the correct gelatin, it has no dye sensitization, there is no DOH added as a hardness stabilizer, and it wasn't coated on corona treated polyester stock, among other problems.