In 1978, so more than 40 years ago, the photochemistry legend Patrick D. Dignan published a highly interesting script with the title
“How to Compound … Simplified Color Processing Formulas.“
Unfortunately, this script is extremely hard to find, and the Dignan family has no further copies either.
Darkroom mate Adrian C. from England was so nice and scanned his copy, Filmkorn now makes it available as a searchable PDF download!
The document is very interesting. While it does not list the exact formulas of the original processes, they would be very difficult to recreate. Rather, it offers a variety of simplified and tried-and-tested alternative processes with often startlingly good (or even indistinguishable) results.
The collection includes recipes for alternatives to the C-41, C-22, E-6, E-4, E3, Agfachrome and some paper processes (including a developer for Cibachrome!).
Great reading, and a printout shouldn’t be missing in any ambitious lab. You can learn a lot here.