I've been using the same tank and reels for about 5 years now--and suddenly in the past three weeks or so, I've been getting blotchy, bubble-like shapes at the same edge of each image on the roll. I've never had this problem before--ever. It's not the camera--film from a Mamiya C330 and a brand new Hasselblad 501CM both exhibit this little "problem". Here's what I'm using:

Ilford Pan-F 120 film Paterson reels and tank (generally with 2 rolls at a time, 1 litre) Ilford Ilfosol-S, 1+14 dilution (as directed by Ilford) school-supplied stop bath Ilford Universal Rapid Fix 1+4 dilution school-supplied clearing agent

I'm prewashing for 30 seconds with constant agitation, then processing for 6 minutes @ 68F (standard), with 4 inversions every minute (as per Ilford documentation). I normally only rap the tank once, right after I pour in the developer; however, in my recent state of desperation, I've begun rapping the tank after every set of inversions. It doesn't help. Stop, Fix, etc. are all standard, and I have never experienced any other problems involving chemistry.

I'm beginning to go insane...I'm ruining roll after roll of film; it's a good thing I'm not professional yet. If anyone would like to SEE what this looks like in an attempt to diagnose, I will be MORE than happy to scan in some negatives so you can see what's going on. Thanks in advance for any help!

Ian Frearson

-- Ian Frearson (frearji@montevallo.edu), February 24, 2000

Answers

You may have wetting agent stuck to the reels; wash them well in hot water.

I think you're simply getting airbells. Try this:

Load only one reel, put it on the bottom, then put the empty reel on top. Use only enough solution to cover the bottom reel. You _want_ that huge air space.

No prerinse, pour in the developer, bang the tank a couple of times, then invert continuously for 30 seconds, at the rate of at least one inversion every two seconds.

Thereafter, invert the tank twice in five seconds every 30 seconds.

-- John Hicks (jbh@magicnet.net), February 24, 2000.

I might get flamed for this, but here goes. I use Patterson tanks too. I don't do inversions or presoak. I use the reel "twirler". Four gentle twists every 30 seconds. My tank sits in a temp controlled water bath so I don't have to lift it out for every agitation. I've never had uneven agitation with this method.

-- Tim Brown (brownt@ase.com), February 25, 2000.

I agree with Tim Brown. Inversion is always likely to produce air bubbles even if you knock the tank each time. I found bubbles more likely with 120 than 35mm. I only 'twirl' - for 10 seconds every minute - and I knock the tank just to be sure.

I'm certain you'll resolve the problem.

Good luck

-- Anthony Brookes (gdz00@lineone.net), February 25, 2000.

I fill my tank up so there's no air in the tank. During inversion the reels slide up and down within the fluid (there's head-room in the tank) but there's no air to trap. I've had no air bells with this technique. The tank is an Omega and I use stainless steel reels. These have plenty of opening between the layers of film so it's difficult for air to become trapped. I knock the tank down onto the bottom of the water bath after each inversion.

-- Don Karon (dkaron@socal.rr.com), February 25, 2000.

Once the film is wet air bubbles aren't going to stick to it; there's no problem at all with a big air space. Air bubbles are formed when the dry film is first immersed, and banging the tank and continual immersions in inversion agitation wash them loose.

-- John Hicks (jbh@magicnet.net), February 25, 2000.

Certainly sounds like air bubbles to me.

Air bubble formation is an entire field of study in itself, but briefly: Air bubbles almost always form and stick at a "seed" site, either a small particle, a surface defect or chemical contamination. Check your developing reels very carefully for any scratches, dirt or water scale. If they're not obviously scratched, give them a good soaking in a strong solution of washing up liquid, with some white vinegar added if you live in a hard water area, and then give the grooves a good scrubbing with a soft toothbrush. After a thorough rinsing they should be good as new.

-- Pete Andrews (p.l.andrews@bham.ac.uk), February 28, 2000.

Aha! The problem was the cleanliness of the reels. A locker-mate who may not have been washing them very well, combined with the hard, hard water in this area, combined to form some barely visible deposits on the film-surface of the reels. I never had this problem before...because I lived in an area with soft water! The lime in the water leaves deposits on everything here, but I had never considered it to be the source of my misery! I still need to invest in some white vinegar to complete the job, but just cleaning them well with hot water, detergent, and a toothbrush was enough to get 3 out of 4 rolls to come out perfectly! Cleaning seems the only way to resolve this, as rapping the tank after each set of inversions (as suggested by some)did not prove effective. Thanks for everybody's help!!!

-- Ian Frearson (frearji@hotmail.com), March 02, 2000.

thanks Ian for poping back and letting everyone know the solution...

-- Nigel Smith (nlandgl@eisa.net.au), March 03, 2000.