I remember reading somewhere that Geoffrey Crawley found that Ilford films performed better in the original Microdol developer than they did in the Microdol-X developer, but my memory is vague as to why.
Perhaps someone here will be know.
Crawley stated that Kodak introduced Microdol X because of Dichroic fogging with Kodak films in Microdol, and that there were no similar issues with Ilford films. It's possible this Dichroic fogging issue was only related to Eastman Kodak films and not those made by Kodak Ltd because Microdol stayed in production here in the UK for a few years longer before switching to Microdol X.
Microdol itself was a replacement for Kodatol/DK20 which was withdrawn due to high Dichroic fogging.
Ron Mowrey (PE) mentioned that Eastman Kodak had issues with Gelatin contaminated from nuclear testing and that this got worse over the years. In the end they stopped using active Gelatins, they processed the Gelatin to strip out the Sulphur sites which give photographically inert de-activated Gelatin. This Gelatin is re-activated using Thiosulphate during emulsion manufacture. One effect was far better control of the emulsions, and repeatability.
When I first began shooting film seriously some Kodak developers had different times (and EIs) for Eastman Kodak Tri-X. Kodak Canada Tri-x and Kodak Ltd UK Tri-X. The variations were down to the differently sourced Gelatins. The switch to de-activated Gelatins meant the differences were eliminated.
Ian
