Quote Originally Posted by Photo Engineer View Post
...Henry Wilhelm knows nothing about DB vs Chromogenic materials. The DB process is much more dangerous to use than any chromogenic prcess. DB materials were never possible to prepare with real camera speeds...Kodak had a DB print process ready to go and its introduction date was 8 Dec 1941. It was called Azochrome...
Henry does know about how the permanence of dye bleach compares to chromogenic's, but not necessarily about use safety or designing a process. He also knows about Azochrome. See pages 25 through 29 of his book:


He never proposed, to my knowledge, a camera-speed dye bleach material. Mostly he opined (to use a recently popular word) that Cibacolor should have been introduced to print from chromogenic negatives.

Quote Originally Posted by AgX View Post
Agfa did the same decades later and failed commercially too.
Yes, that's in the same book pages too.


Quote Originally Posted by Photo Engineer View Post
...POS-POS print systems have an inherent flaw. You are basically multiplying the slope of one curve by the slope of the other curve, (original slide x print material) to get the final dupe image. If your original has a perfect capture and a slope of 0.3, and if the print material also has the same slope, the result is a slope of 0.09, which is a reduction in contrast. This is why you must use masks to adjust contrast and masks to adjust color.

No pos-pos system without these masks has ever been a big success. Thus, high end labs or printers use masks and get superb prints but at a high cost in time and materials. So, most simple pos-pos printers have failed. Or, they had commercial difficulties.

I know Henry personally and we talked for about 3 hours on his last visit to Rochester. He is avid about what he does, but just like me, neither of us is always right...
I'm not so sure he was wrong that a dye bleach negative paper like Cibacolor would have been much better than the Ektacolor/Fujicolor versions we've had to live with. Especially versions sold in the decades between when Ciba-Geigy decided against marketing it and 1993 when the book was released.

My long-term use of and love for Kodachrome was entirely centered around projecting it, both stills and motion pictures. Direct prints from reversal films, whether Kodachrome or other transparencies, were never capable of duplicating that viewing experience. I didn't try forcing them to.