Keith you actually high-light a major difference between European and US photography, it's there in the images made by European photographers in France & Germany particularly before WWII.

While it's there in history, in prints, collections etc it's also present in the developers, quite strange to us now but it was a different way or approach to working. This carries on after WWII where even Kodak are making & selling developers never seen or made in the US, and as PE (Ron Mowrey) has indicated unknown to US researchers).

Ian