Manufacturing an insert for Jobo 3063 Drum
I’m trying to gauge the interest level among ULF film users for a precisely manufactured insert for the Jobo 3063 drum. The proposed product would allow even development of sheet film between 8X10 and 12X20—something I haven’t been able to achieve consistently with the 3063 alone.
Because I was dissatisfied with the results of film developed in the 3063 drum, used as provided, I started experimenting with an insert based on the design of the Jobo professional drums, with the film wrapped in cylinders within the 3063. Since there isn’t any standard tubing of any kind that has the right dimensions, it took awhile to come up with a prototype, but I recently finished and tested an insert that allows development of two 12X20 films. There are two thin-walled (but strong) tubes with an inner circumference of 12.25 inches. Fitting two tubes of this size in the 3063 requires that they be slightly oblong, but this appears not to affect the evenness of development. The agitation is vigorous and random enough by this method to produce neutral areas--such as open skies--that are smooth and free of the “banding” characteristic of the negatives I developed in the standard 3063. I should add that I have quite a bit of experience using Jobo drums and that I worked hard to produce good negatives with the unmodified 3063—succeeding infrequently, and not knowing quite why when I did. In short, the results weren’t predictable.
As constructed, the insert would weigh, in combination with the 3063, no more than the 3005 drum, and have some slight relief running the length of the cylinder walls so the antihalation coating would be released—probably a splined pattern with just enough depth to support the film well, while allowing solutions to circulate under it. The user would slide the insert into the drum and put a bead of caulk around the top edge with silicone to seal it. (Silicone is durable, but can be removed so the insert could be taken out if desired--though the enhanced performance would likely make it unnecessary.) The insert would use a maximum of 1000mm of solution and would require a lid from one of the other Jobo professional drums (3005, 3006, or 3010)--the lid supplied with the 3063 won’t work because the cup underneath projects too far into the drum.
The prototype I made was intended only to see if the configuration would work. Having determined that it will, I’m interested in having a long-lasting version injection molded. By the way, it would be helpful to find out what kind of plastic the Jobo 3000 series drums are made of, if anyone happens to know. I only need one insert, but, due to the cost of production, the only way for me to do this would be if other ULF users wanted such a product, too. I don’t know yet what the setup costs would be, but if there’s enough interest I would explore it further and come up with a price. For now, send me a personal message on APUG or at firstname.lastname@example.org and tell me if this is something you would buy if priced within reason. If there’s enough interest, I’d have computer-generated drawings made and send them to a fabricator for pricing on molds and manufacture. Then I’d need to collect some money to go forward. I’ll try to answer any questions you may have. Thanks.