In my post of 17 January, I suggested that the Rondinax 60 was introduced in 1937, appearing in the 1938 edition of BJPA. I received a 1937 French Agfa Catalogue this week and sure enough the Rondinax 60 (no sign of the Rondinax 35) is shown as being new: Nouvelle cuve pour le développement en plein jour.
Here is the cover of the catalogue and page 21 showing the Rondinax:
The boy looks as if he is getting rougher washing than the film in the tank. That water looks cold.