Searching for information on daylight-loading developing tanks I cam across references to the Optochrom Automat. I had never heard of this one. However, they seem to appear on eBay occasionally; indeed there is one on the US site right now. I have added the images to my Pinterest Board (link provided on a page on this website).
From discussions about 10 years ago on German and US fora it would appear that it was on sale in the 1930s. Here is an illustration from an RG Lewis (UK retailer, still in London) 1936 catalogue:
The photographs of the tank on eBay show that it was made in Germany. One contributor to a German forum found that all the parts were marked ‘PAG’. He identified the makers as Presswerk AG of Essen, producers in the 1930s of Bakelite objects.
If the information from a member of a German photographic forum, that Optochrom was a company registered in Augsburg, is correct then is it mere coincidence that the inventors of the Rondinax (see Patents page) were from Augsburg or was there a connexion?
Loading seems to be similar to the Austrian Simplex tank (see my post of 22 October). The pulling of the backing paper appears to drive the film into the spiral from the outside. A plate is used to blank off the film slit in order for liquids to be added to this vertical tank. A contributor to a forum had tried it but it did not appear to work very reliably. The Rondinax method of loading the reel from the centre overcame this problem even though an additional step and light-tight container for the separated film was needed.
Compared to the Rondinax 60 (or Essex 20) this one sounds as if it is for collectors and not users.