JOBO CPE-2 streaks with PMK Pyro - hmmm

Hello,

I've been trying out a CPE-2 to develop 8x10 negs in PMK Pyro and have noticed strips of increased density in the prints that coincide with the areas on the neg where it sits on the ridges that the plastic clip thingies sit in the tank (the ones you replace for different formats) ...

There is one ridge on one side of the tank and three on the other, with 8x10 you put a clip thingy on the one on one side - and then one on the centre ridge of the other - leaving two ridges on either side that contact the base of the neg - Jobo tank users will get what I mean...

I end up getting less staining in these two areas - developing two negs at once I'll get one strip on each - either side depending on which way goes in first, top or bottom ... (an yes I'm putting the negs in correctly with the emulsion on the inside curve, not resting on the ridges - I would expect much worse results had I done this wrong)

I cant actually see the strip of less density in the neg, which is to say the silver, so I'm assuming it must be in the stain - ok for scanning, silver i guess, but ruined for alt process

Boo hoo !

I'm back to my trays for the time being - what am I doing wrong ? standard PMK soup - Arista Ultra Edu and FP4 12~16mins 20~24deg depending on subject/lunar cycle and mood - agitation setting '1' (slower option)

Agitation that's too slow will streak film with PMK. I use the "P" setting, which is about half way up the speed scale.

I have two settings - well, ok three - 1, 0 and 2 - I'm using 1 currently

Hmmm, how much would I decrease development with the faster agitation ? It really rockets around compared to the slower setting...

What I am concerned with is that the increased stain is right down where the film connects with the ridge (no mistaking it, same on every neg) - because of this it's ever so slightly raised I'm assuming because of this the the liquid connects with it with a little more 'force' in this area so to speak - its not the same streaks you get with say tray dev and no agitation (relatively concentrated areas etc..) - so will faster agitation really help in this case ?

Has anyone experienced the same problem ?

Hi Nick, the problems you are seeing were behind Sandy King's search for an improved Pyro developer for use in rotary processors.

In this article, Sandy gives his reasons for the development of Pyrocat HD

SandyKing said:

I developed the Pyrocat-HD formula primarily to eliminate problems I had experienced with other staining developers using rotary processing. By rotary processing I mean development of film in Jobo, in BTZS type tubes, or in print drums used on motor bases. I used PMK for many years with tray processing and was very pleased with the results. However, when I switched to rotary processing I began to experience a number of development problems, including high general stain, streaking on the emulsion side of the film, and unusual pressure marks on the base side of the emulsion that resulted from contact with the surface of the tube or from the ribs. Sometimes the streaks and pressure marks would not be visible when looking at the negative through visual light, but they would show up later during printing with UV light. I switched to Rollo Pyro, and while this reduced the high general stain it did not solve the problem of streaking and pressure marks. The use of Pyrocat-HD has eliminated all these problems in my own work and I strongly believe it is by far the best Pyro developer for use with rotary methods of development.

Click to expand...

I have been using Pyrocat HD for the development of 5x7 negatives in Jobo print drums, and have not seen any of these problems, so it might be worth trying out one of the Pyrocat family of developers.

If using a roller base for agitation, Sandy recommends removing the drum every couple of munutes and giving it some sideways agitation to break up laminar flow patterns, but as additional comment in this article, Clay Harmon recommends using this procedure for Jobo processing as well, though to date I have not seen any streaking with my negatives.

Nick, I'm assuming you are using the smaller of the two 2800 tanks, the larger one is a two piece and is designed for 12x16" paper (or negs).

The CPE2 is (or was) the entry processor to the rotary system, your processor, going by it's two speed setting, is about 18 years old, give or take. It has a slightly stronger motor than the original, but not as strong as the motor in the last single speed CPE2 unit.

As far as I can work out after talking with people who knew these things inside out in Germany, the two speeds were basically there to control the outside drum speed to be more or less equal, depending whether you were using the 1500 or 2800 drums. The fast speed was for the 1500 drums and the slower speed was for the 2800 drums.

That said, I develop my films either in the 1500 or 2800 series of drums at the same speed, slow. I don't think the speed of the processor is going to make too much of a difference to the actual developing of the emulsion, at least I've never noticed it.

Your problem is the drum wall, or where the film is physically touching something. Perhaps after developing and stop bath have been used and you have done say ½ of your fixing, you could pull the film out and finish the fix and the rest of the process in a dish. I understand exactly the clip situation you are describing.

The main thing is to get good even developing, which the print drum will do.

Mick.

I think the quote from Sandy (kinda) hits the nail on the head:

...streaking on the emulsion side of the film... that resulted from contact with the surface of the tube or from the ribs.... sometimes the streaks and pressure marks would not be visible when looking at the negative through visual light, but they would show up later during printing with UV light...

Click to expand...

I'm getting less staining, not sure if he is talking about more or less or just general badness...

Pyrocat-HD huh - great - I'm only borrowing the CPE2 at the moment which was going to be a possible swap for my Jobo/LPL color enlarger (6x7 which I never use now) - I'll put it on the shelf and tray dev until I do another bulk chem order and get the required bits and bob for the pyrocat-HD, and I have some new 8x10 Rollei R3 here with the RHS developer which is non staining so I'll give that a crack in the tank, cant remember which tank it is but I cant imagine a bigger tank fitting in the pool, I recall a '2' being involved in the graphics on it and the magnetic base can be separated, suspect it is a 2800 series...

I might try with a non-important exposure angling it longitudinally every 30 secs or so when I am developing as has been suggested, but I reckon surface tension will always keep some PMK around the offensive area ...

Good to have an answer - thanks!

Just use the 3005 Drum. The film should be prewetted before you put it into the water filled upright standing 3005 drum. Then close the cap and fill the drum completely up to the gear with water. Now you have to spend some money for a bottle with compressed nitrogen. Fill the 3005 drum with nitrogen by inverting it and replacing the water with nitrogen through a hose. Now no oxygen is in the drum and very little general stain will occur. My negatives are very evenly and cosistently developed and show less general stain than developed in open trays by the shuffle method.

ha ha

Nice work - perhaps a little too involved since I'm just borrowing the system

schlger said:

Just use the 3005 Drum. The film should be prewetted before you put it into the water filled upright standing 3005 drum. Then close the cap and fill the drum completely up to the gear with water. Now you have to spend some money for a bottle with compressed nitrogen. Fill the 3005 drum with nitrogen by inverting it and replacing the water with nitrogen through a hose. Now no oxygen is in the drum and very little general stain will occur. My negatives are very evenly and cosistently developed and show less general stain than developed in open trays by the shuffle method.

Click to expand...

Depending on how far away the local welding supply store is this could be an excessively long pre-wash.