I am consistantly having problems with too much edge(outer 10%) density in my negatives. Problem appears to be independant of developer, camera, and film. I suspect the problem is in agitation but am at a loss how to correct. The tank I develop in holds three and a half (three 120's and one 35mm) reels. Is this normal - some photographers tell me that you should expect some density increase towards the edge of your negative. What I see seems excesive though. I have to DOUBLE my exposure time on the edges of my prints just to get them even left to right! Could the problem stem from turbulent flow of developer as it passes reel wires? Absolutely any help would be appreciated.

-- Russell Pillers (pillers@med.unr.edu), March 15, 2002

Answers

Response to 120 Ddge Density Problem.

I get pretty uniform density across the frame. What you described doesn't sound normal. You never had anything like that in 35mm? Can it be fog? Is your film and backing paper rolled up tightly and kept in a dark place after shooting before processing?

You could send one roll to a lab to see if they have the same density increase towards edges.

-- Ryuji Suzuki (rsuzuki@rs.cncdsl.com), March 15, 2002.

Response to 120 Ddge Density Problem.

The only thing that comes to mind is the possibility that the reels can move up and down inside the closed developing tank during agitation. In my case I use a single reel tank, and I took a 120 film spool and clipped the rounded ends to make a spacer that prevents my reel from moving up and down. I have never had the problem you describe. If your reels are immobile, then I would try a smaller tank and less vigorous agitation.

-- Ed Buffaloe (edb@unblinkingeye.com), March 15, 2002.

Response to 120 Ddge Density Problem.

This does sound like an agitation problem. Edge build up will establish itsef during the first 30 - 60 seconds of development. It can be caused by either too much or too little agitation. Not much help, I know, but you need to run a few test rolls and change your initial (first 30 seconds) agitation with each run and gage your results against each other. A pre-soak in water will sometimes help. But it should be noted that no manufacter recommends this and it will create a need for you to shorten your total development time.

-- James Megargee (jmegargee@nyc.rr.com), March 16, 2002.

Response to 120 Ddge Density Problem.

I had the same problem discussed on a german discussion forum 1-2 weeks ago. Answers were not very helpful. It clearly araises from different developer agitation on the edges and center of the roll film strip. I never saw it on 35mm. It is highly dependent on the type of developer and film used. "Thick" emulsions and highly diluted developers show the strongest density geadients. e.g., APX400 in Rodinal gives unusable negatives when rotary processed; on the other hand, Tmax 100 in Xtol stock has almost (almost!) no visible densitiy differences.

You can mistake it for a light leak problem, but a light leak effects mainly the unexposed border (and give more base density), while in uneven processing the boders are clear.

I suppose, many photographers burn in the edges of their prints routinely, if they have the "feeling", that they are too bright, but don't think further of the origin of the problem. If you have seen the effect on some prints, you start to recognize it on many others (a learning effect, not a phobia).

You can minimize the problem with (*)prewash 5 min (*) maximum rotary speed (*) use highly active developers (Tmax, microphen, ultrafin sf....)

I dont want to mess around with my negs, so I quit rotary processing of B&W-rollfilm completely and changed back to inversion.

Georg

-- Georg Kern (georg.kern@uibk.ac.at), March 17, 2002.

OK, here goes. I believe the problem is essentially _insufficient_ agitation, perhaps with sliding reels contributing. So try this...

Load film onto only two reels and put them in the bottom of the tank. Put empty reels on top as "spacer" reels to prevent the loaded reels from sliding a lot. Once again, that's up to two reels loaded with film on the bottom and however many reels or combinations of reels on top.

Now..the important part...use _only just enough developer to cover the loaded reels_. No more. You want that big air space.

Pour in the developer, bang the tank a couple of times, then invert it _briskly_ at a rate of two to three inversions per five seconds for the initial 30 seconds of the development time. None of that "gentle" stuff. Then give it two to three inversions in five seconds every 30 seconds for the remainder of the development time.

Finish processing as normal although there's no need to use more of the other solutions than is needed to cover the film.

This may seem counterintuitive and illogical, while otoh perhaps millions of 120 rolls are developed yearly dip'n'dunk, which is pretty much the same thing, so rather than thinking yourself out of it just give it a try.

If this turns out to cure your edge-density problem you'll most likely find that your negs are contrastier and probably overall denser than normal; that's an indication that the agitation method that led to excess edge density was actually a case of weak, underdeveloped centers rather than excess edges.

This assumes steel reels, which I gather from your message you're using.

Some plastic reels somehow trap and hold developer in the image area that's underneath the plastic spiral with 120 film; these reels include the old Unicolor reels and the white Jobo 1500 reels. The only solution I ever found for the wavy line of edge density (usually only one edge) that actually mirrors the spiral was to use Jobo 2502 reels. Those reels have tiny molded nubs within the spiral that hold the film's surfaces away from the smooth spiral itself and permit the free flow of solutions all the way to the film edge.

-- John Hicks (jhicks31@bellsouth.net), March 18, 2002.

I had this problem years ago. I tried both less and more agitation and could never get it right. My solution: I found someone who *could* develop 120 film evenly and paid them to develop mine. That was 30 years ago and I've never developed a roll since. (Developing film has to be one of the most boring things around, anyway!) Seeing that you're in a university, I'll bet there's a photo program where you could find someone. I currently use a guy who is a professional photographer, but does lab work for a few studios, including 100's of rolls per month - beats me why he does it! Check the yellow pages and ask around, too, maybe at your local photo store. You probably won't have trouble finding someone who will do whatever developer/time/whatever you want.

-- Andy B. (buckwiet@yahoo.com), March 19, 2002.

Russell, It occurred to me last night, are you using Photoflo in the same tank... This sounds like contamination on your reels from the flo. Wash everything in HOT water and use LFN instead. It comes in a little squeeze bottle and all you need is a drop or two. Much cleaner than Photoflo. Hope this helps.

-- Scott Walton (walton@ll.mit.edu), March 20, 2002.