Quote Originally Posted by Alan Johnson View Post
Perrin gave a 1956 discussion:

He did not mention the type of developer, the effect of which was mentioned by Adams:

Presumeably there must have been some later proprietary work, I have not looked through the references in Dr Henry's book.

Well Kodak's research into High definition Developers at the Kodak Research Laboratories, Harrow, resulted in Kodak HDD their proprietary developer which was never made or sold in the US. This developer competed with Ilford Hyfin and Paterson Acutol-S.

It's often forgotten that Kodak Ltd, UK sometimes made and sold products in Europe never available in the US. In terms of developers 3 come to mind, HDD, Kodelon and D163.

Kodelon, which was Kodak's equivalent of Agfa Rodinal and Ilford Certinal was introduced some time in the 1930's and would have been based on pf CEK Mees 1908 earlier research at Wratten and Wainwright. D163 was Kodak Ltd's main Universal film and paper developer.