At some point, during the 30s, Agfa marketed a daylight developing tank, named Agfa Rondinax 60, for 120 film negative. It was a marvel of its time, allowing the loading and processing the film in plain daylight. The idea was a brilliant one: insert your roll of film in the tank, attach it to a plastic leader, put the lid on, crank that handle until the film is rolled onto the dev reel. The amount of dev and fixer as minimum, as the film sloshed around in the bath at the bottom of the tank. I have no idea how popular was this tank, but apparently Agfa produced quite a lot of these, so I guess they were common.
The three versions of the Agfa Rondinax / Rondix for 120 and 35mm film format
Post war, Agfa took out another two models, the Agfa Rondinax 35 and 35U, which were dedicated 35mm film format developing tanks. And daylight ones too, keeping the same principle of the Agfa 60. A model named Agfa Rondix 35 was also produced, a tad simpler than the rest of these above. These model were very popular, as the 35mm format became more of a norm with the amateur photography communities.
So why am I blabbing about some device that deals with any other film format, but the Minox one? Well, it would appear that someone, somewhere, managed to print such a daylight dev tank for Minox film format (9.2mm, 8×11). It has even been named “The Rondix Agfa daylight tank re-designed” and for all intents and purposes is just that: a modified tank, 3D printed (I was told the method is called “Fused deposition modelling, or FDM”, that takes Minox format films and loads + develops them in daylight. A copyright infringement rings like a bell here, in my opinion, but that’s a different issue, not discussed here. That said, it’s a very interesting item, and I for one wish that it would be a good addition to the Minox community and a real challenge to Minox dev tank. Well, is it?
I do not know this, mainly because I haven’t bought one such item. But this doesn’t stop me from discussing this tank, at least at a theoretical level. First of all, I do hope this tank has been properly made lightproof, because if not, it’s useless. No idea if the Rondinax had light seals (probably not, in terms of felt ones), but I am certain it has good interlocking parts which made the film safe inside. The bakelite which is the material used in the original Rondinax tanks is very smooth and makes the interlocking of the lid and such quite easy to keep dark inside; I do not know about this 3D finish, which has a bit of relief to it. I hope you get my point on this one.
I would also want to see the interior of the tank, mainly the method of hooking up the leader and the drum/reel/thingy (or anything resembling one). The film, in the Rondinax fashion, is not being “loaded onto a reel” in the classic fashion. Instead it is affixed in some manner onto a small central drum and the crank is operated to take the film out of the cassette and rolled onto that drum. Once the crank stops because the film has been completely pulled out from the cassette, then the direction of cranking is reversed. One has to crank both ways for the entire duration of the development (and fixing) process. One thing to consider with Rondinax, I should think.
A paramount aspect of the usability of this tank is its opaqueness; sometimes, the resin used is not an absolute black. This is the reason why some 3D printed Minox cartridges fail, or indeed some other subminiature cassettes are fogging the film inside.
These two aspects are of interest here, to be honest. Anything else, such as the solidity of the tank, possible contact of film with some internal parts that can cause scratches, crank effectiveness, internal pieces and their resilience to stress and multiple turns of the handle, the seal around that handle, are of course equally important.
For those of you who want to understand how the Agfa Rondix 35 (the original) operated, please see the manual here. The manual is written in German, English and French.
Photographs depicting this adapted “Rondix tank” are from the seller’s page.