rotary development

[phil sweeney]

I'd like to pickup a unicolor print drum and motor, for 8 x 10 film dev. I have read most of the posts and threads on the subject and still have a couple of questions. Though the print drum is preferred, can the film drums be used (including the cibachrome drums etc)? I am aware one could back the film with fiberglass screen etc.

I will probably use pyrocat, but I use ABC also. I understand that rollopyro is some variation on ABC? On solution and dilutions: I recently developed, in tray, a few negatives in WD2D exposed from a step tablet, for test purposes. On one occasion using less total solution than normal I noticed excessive stain and could see the developer was darker than normal at the end. I believe this is described as oxidation of the developer? I have seen this in tube development for all the pyro developers and therefore do not use tubes. A repeated test did show expected minimum stain with more volume at the same dilution. I know excessive agitation should be avoided but can see that more solution does combat the problem. I have found ABC does not discolor as much.

I would like to know if anyone has more knowledge on using more solution than the minimums recommended in rotary processing?

Though I have no tray processing problems I am looking to have a tighter control on negatives for alt printing and believe drum processing can achieve that.

[John Kasaian]

phil,

I don't see how a unicolor film drum would work---they were designed to hold film spools not paper. I fooled around with one a few years back but no luck. I don't remember exactly what the problems were but I'm thinking it had something to do with the size of the drum and the lid. Maybe you could get it to work but it would take some extensive modification---not worth it IMHO.

[sanking]

Lots of questions there.

First, the print drums can be used to develop film. I have been developing my ULF film this way for years. Whether or not you need an insert I don't know. I don't use one with either Beseler or Unicolor drums and have seen no sign of uneven development. From time to time others have reported streaking caused perhpas by the ribs in the drums, especially with staining developers. BTW, I much prefer the Beseler drums because they are much less prone to leak. The Unicolor drums have gaskets thaet go bad with time. But if you buy a Beseler drum make sure you get the divider inserts so you can optimize use for different film formats. With the 16X20 Beseler drum you can put in the inserts to develop either one sheet of 12X20 film or two sheets of 7X17.

You already know Pyrocat-HD and ABC Pyro. Rollo Pyro is more of a super-charged PMK than it is a variaetion ion ABC. It gives very low stain with rotary processing, similar to Pyrocat-HD. A 2:4:100 dilution of Rollo Pyro gives almoset identical speed and contrast at the same time of development as a 2:2:100 dilution of Pyrocat.

You can do several things to combat excessive general stain with rotary development, but the simplest is to just increase the ratio of A to B solution when mixing the working solution. For example, instead of a 1:1:100 dilutin of Pyrocat-HD try 2:1:100. Although I have not tried this with ABC and Rollo Pyro I feel certain that it would work.

[ronald moravec]

Have never used Pyrocat, but did try PMK in a rotary drum. The simple amswer is it did not work as the developer oxidised rapidly. Even tried replacing it with fresh 1/2 way thru.

In Gordon`s book he recommends using a nitrogen blanket pumped in down the Jobo lift.

I have done sheet film it in trays and it works but you still get a lot of oxidation which you compensate by longer times. Same with open tanks and reels.

The best method overall I found is a closed tank like my 35mm and 4x5 Nikors or the Jobo that takes the 6 sheet 4x5 reel and used as an inversion tank. The sealed tank prevents all but very minimal oxidation. The PMK comes out looking freshly mixed and the times are about 60% of those used in open systems. Stain is perfect.