This problem cropped up only a week ago and it only happens when I develop two 120 rolls in a large stainless steel tank. I've done this before dozens of time with no problem but only last week I noticed on the bottom roll dark patches running parallel to the bottom edge of the roll relative to how it rests in the tank.

The patch seems darker on the part of the negative that sits on the outer part of the reel and less apparent on the part that's further in the middle of the reel.

Just for the record, when developing two rolls of 120 I mix the delveper and pour it into the empty tank - turn off the lights and roll the film onto the reels -- slowly lower the reels into the tank -- turn on the timer and start aggitating. When the developer is finished I turn off the lights again -- pour out the developer and hold the tank under running water for two minutes allowing for five complete water changes before pouring in the fixer and turning the lights back on.

Any ideas on what's causing these patches? Could it be because I'm not using an acid stop bath?

-- David Parmet (david@parmet.net), October 02, 2001

Answers

I'm afraid I don't have an answer for what might be causing the marks. I can say, however, I see nothing wrong with your technique, and I do not feel the problem is due to using a water bath in lieu of an acid stop. I use the same procedure, and have for a mountain of film, and haven't seen this problem. So I don't think an acid stop will fix it.

Have you changed anything in your procedure of late? What developer do you use. What fixer? Is it possible your fixer is nearing exhaustion? Why not try all new chemistry with immaculately clean tanks and reels and see if that does not eliminate the problem.

-- Ted Kaufman (writercrmp@aol.com), October 02, 2001.

Is it possible that the roll was exposed to light, possibly because the paper was not wound tight? Can you put a picture of the negatives on a web site?

-- Michael Feldman (mfeldman@qwest.net), October 02, 2001.

Ted - I use Ilford Rapid Fixer mixed 1:4 and I don't reuse it. I normally fix for 4 minutes followed by two minutes under running water, a minute in PermaWash and another two minutes rinse followed by a minute in LPN. I use Hewes stainless steel reels and I rinse them after every use.

Micheal - I thought so at first but it doesn't look like light leaks and this is the second time it's happened.

Like I said, I've never seen this before.

-- David Parmet (david@parmet.net), October 02, 2001.

I'm stumped, David. Everything sounds fine to me. I'll be interested in hearing what it is when you finally resolve it, though.

-- Ted Kaufman (writercrmp@aol.com), October 02, 2001.

Dont't think too complicated (I'm waiting for someone who will explain it with the "Xtol-failure"). That's definitely just stray light on the film edges. It may happen while loading or unloading the film or while preparing it for development. It can occur occasionally, because just a few seconds more or less in the light can make all the difference. Additionally, high-speed film is more susceptible than slow films (surprise). Some types of film seem to be wound looser than others (from factory on). Heat, vibration etc. also may loosen the film. Other (unlikely) explanations: the magazine leaks light (but in this case the darkening would affect a greater area) or the fixer didn't reach the film at areas, where it is in contact with the reels (but this would cause shiny patches, not dark).

-- Georg Kern (georg.kern@uibk.ac.at), October 03, 2001.

I think it sounds like a light leak. If your roll was would tightly then check your felt traps in your camera back. You can find replacements for this at this address:http://www.micro-tools.com/ Merchant2/merchant.mv?Screen=SFNT&Store_Code=MT Cheers

-- Scott Walton (f64sw@hotmail.com), October 03, 2001.

I will find a similar problem if not careful loading 120 in the sun and also if I do not roll the finished roll very tight. The first case affects the beginning of the roll and the later affects the end.

-- Mike (watgo@aol.com), October 03, 2001.

Just to expand on the discussion a little...

Sealing 120 roll films has always worried me. The glue that sticks the paper down/around seems to be pretty good, but if it ever lets go your film will be stuffed. Always possible when trying to change rolls in a hurry! What I do is I keep a supply of small rubber bands in my bag and add one for insurance. Also, if you away from home for days/weeks, having something nice and solid to keep exposed rolls in is a good idea. I've seen some very nice machined aluminium canisters for 120 roll film but they were quite expensive. I have some M&M (sweets) containers that hold a roll but they are not light proof (might be water proof though.. the lids snaps shut pretty well, must test that!), just a bit of protection from bumps.

-- Nigel Smith (nlandgl@unite.com.au), October 03, 2001.

I think I've solved my problem. The dark marks were from over-agitation. Basically with two 120 reels in there there is still enough room for them to move around when I aggitate leading the bottom reel to get too much aggitation.

I ran a test with two reels and a 35mm reel in there to hold them tight. I filled the tank up to the top and developed normally. No staining.

You learn something new every day....

-- David Parmet (david@parmet.net), October 14, 2001.

That used to happen to me until I stopped agitating in figure eight motions.(Yeah I know.) I now agitate with vertical motions and this seems to provide even development throughout the negs. Mark

-- Mark (marktt@nac.net), October 22, 2001.