In researching processing B&W films using a JOBO processor, I've come across the question, "to pre-soak, or not to pre-soak"...I plan doing tests in both instances, but what is the word on this board? More importantly, another dilemma I've gome accross is the problem of dilution of developers. Currently I'm using D76 1:3 and XTOL 1:2. For both of these films, the manufacturer advises using 100ml stock per roll of 135 film, regardless of dilution. The volume of developer required for processing 4 rolls of 135 in a JOBO tank is just shy of of 500ml. Simple math tells me that I won't have enough stock developer. In the case of D76, I'd be willing to drop to 1:1, but that still won't solve the problem. This will give just under 250ml of stock for 4 rolls! Is there an obvious solution that I'm missing here? Is my math "fuzzy?" Please help...many thanks in advance.

-- Paul Klingaman (pklingaman@hotmail.com), June 06, 2001

Answers

Paul, Jobo states on their website that no presoak is neccesary with XTOL. My personal experience has proven this to be true. I use XTOL 1:1 in my Jobo. I generally maintain 100 mls of stock per roll (or two hundred mills mixed developer per roll)as per Kodak's reccomendation. This does limit the volume of rolls that can be processed at one time.

Kodak's reccomendation of a 100ml stock minimum per roll, and a stock dilution of no higher than 1:1 is thereway of insuring the user against the so called "failure" that some users have reported.

Can you use greater dilutions? Sure. Can you use less than 100 ml of stock per roll? Sure. Will you have to increase development time? Yes. Wll you have consistent results using less than 100 mls of stock per roll? Somewhere there is a threshold where too little stock per roll will create "failure". You will have to run your own tests to find that out.

-- Paul Swenson (paulphoto@humboldt1.com), June 06, 2001.

Paul, all - Kodak, Ilford, etc. do not recommend a pre - soak in water prior to development. In fact Kodak strongly recommends that you do not pre-soak. All times, etc that they recommend are based upon dry film going into the developer. As for you developer volumn question - shoot a some rolls and run a few tests. Film and developer are cheap and anyone that has established their exposure/development times will tell you that it took many rolls and many tests to get to their proper times. If you screw up a few test rolls - so what. You retest and and go from there. Its how we all learn.

-- jim megargee (jmegargee@nyc.rr.com), June 07, 2001.

The noted volume on a Jobo 1500/2500-series tank is the least amount required, you can run higher volumes. E.g. for watering a single film after development in a 1510 (noted volume 130 ml) I use 200 ml, and have the impression I get 200 ml back using the lift. So a 1520 should be fine for 2 films by increasing the volume from 260 to 400 ml.

And this math might solve my Xtol problems: Using a std. test roll with 10 steps plus some pictures everything was fine with 65 ml stock plus 65 water, because it was 65 ml for half a roll. The actual run of two TMY films with 130 ml stock and 130 ml water gave very thin negatives. I might go to either 100 ml stock for 1:1 or straight Xtol (130 ml).

Regards,

Wolfram

-- Wolfram Kollig (kollig@ipfdd.de), June 07, 2001.

The only need for a prerinse may be to prevent airbells. If you get airbells without using a prerinse, then give a short (one minute or so) prerinse. A prerinse for that reason can be used with Xtol if need be.

Quite a few people have had trouble with Xtol, particularly at high dilutions, thus Kodak's recommendation of 100ml stock. While you could use less, you'd be getting into the area of a known problem.

As for D-76, I've found no difference in EI, CI or curve shape between using 100ml stock and 50ml stock, as you'd probably want to for the 1:3 dilution. That's with HP5+, Delta 100, TMX and Fuji Acros 100.

BTW, the volume required per Jobo is that amount of solution needed to cover the film; you can use more, although the CPE-2 is limited to 600ml.

-- John Hicks (jbh@magicnet.net), June 07, 2001.

Thanks to all for the response. I'll address most of the issues in this thread by sharing the results of the tests I did last night:

Pre-soak... I did four strips of 135 HP5+ in D76 1:1 at 20 degrees for the ilford- recommended 11 minutes as a starting point. Two of these strips I pre-soaked and two I did not. The densities of all strips looked ok, however there was inconsistancy in the two pre-soaked strips. Both strips seemed to blow out the highlights a bit, one worse than the other. The two non-presoaked rolls came out pretty close to ideal. My conclusion was that the blown-out highlight problem could probably be solved by altering the development times, but there's just no reason to presoak, adding an extra step and 5 minutes, and worrying about the inconsistancy, when the non-presoaked film processed so well.

1:1, stock, or 1:3- Because the recommended time for HP5+ in D76 1:1 came out so well, I decided to keep the processing times consistent with what Ilford recommends for stock, and 1:3 dilutions...7.5 and 22 minutes, respectively. Again, I was pleasently surprised at how close these times are to ideal for my darkroom setup. I developed one strip each in the latter mentioned dilutions, and each strip printed almost identical. The 1:1 and 1:3 dilutions were almost duplicates of one another...1:0 difference was subtle, but there. Because the results were so close, I decided to go with 1:1 for the following reasons: 1) Not comfortable with development times approaching 5 minutes with no gain in apparent sharpness. 2) The problem mentioned in the original post regarding amount of stock solution per roll(see below).

Fine-tuning development time... Because the 11 minute Ilford rec. was close, I chose to develop another 4 test strips in the following increments: 1) 8 minutes 2) 10 minutes 3)12 minutes 4)14 minutes. Again, these strips were all done in 1:1 D76 at 20 degrees. 8x10 enlargments of each strip were made using diffusion enlarger(cold light). The 8 minute strip printed a bit too flat. The 10, 11, and 12 minutes strips were close...the 14 minute strip showing a bit too much contrast on the final print. The 11 and 12 minute strips were almost non-discearnable, and the 10 minute strip seemed to print the best.

Results: Ilford's suggested time(11 minutes) for HP5+ in D76 at 20 degrees were just about right on for my setup. The ideal development was almost 10 percent lower than this recommended time, coming close to Jobo's suggestion to decrease development time 15 percent (from times given for inversion) for rotary processing. As for the dilutions, I added about 60 ml more than Jobo's recommended volume for the 1520 tank. This gave me 130ml stock D76, 130ml water...or 65ml per roll of 135 film. It should be noted that the film was not an entire 24 or 36 exposure roll...the test strips were apporoximately 5 frames long, coming from the same stock of 100ft roll HP5+. One more test will be needed for a full roll at 65ml stock before processing any real images.

Thanks again to all who contributed. Hopefully these results will be of interest and aid to anyone following this thread.

-- Paul Klingaman (pklingaman@hotmail.com), June 07, 2001.