Ian;

A&T state that the stability may have been one of the reasons Kodak HDD was discontinued. I know that. And, that is my point.

A Metol version of Rodinal is potentially doomed to failure through instability regardless of sulfite level. IDK for sure, but it points that way. Metol is much more reactive than pAP as a reducing agent, and if it outstrips sulfite as a reducing agent, then sulfite will not preserve it very well at all.

Kodak HDD is not the "opposite" of Patrick's formula, it is an analog of his formula.

The Kodak HDD design was optimized for older film emulsions as stated by James. It was dropped when emulsions were redesigned rather than continue to produce a marginal product and redesign of the developer was probably considered to be uneconomical. Rodinal was probably redesigned at that time due to the same changes. IDK, but I have mentioned before that changing emulsion types would probably require updated developer formulas.

Not knowing the details, many authors might ascribe things the way Crawley did regarding optimum developer/film combinations. Only insiders might know when an emulsion change would change the response of a product to a given developer.

PE