Spotty negs

Discussion in 'Black and White' started by giverin, Feb 25, 2013.

  1. A few months ago I was at a friends wedding and was shooting TMY at 800. I developed in TMax developer and I got a lot of small white spots on my negs. I figured they were too small for dust and I dry the film in a dust free environment anyway. I wondered if the spots were due to the film being in the stop bath for too long (about a minute) so from then on I started 2 stage stop bath procedure..... 15 seconds in stop bath followed by a minute in plain water. For the next couple of months I was shooting Neopan 400 and HP5+ in D76 and Neopan 1600 in Microphen... all with my new stopbath system and all was fine.
    Then last week I was at my son's wedding and I was shooting TMY at 1600. Again I developed in TMax dev. The dreaded spots appeared again (see 100% crop). Is this still a stopbath issue? I've read elsewhere that TMax dev can react with acid stopbath and cause pinprick blistering in the emulsion. Does this sound reasonable?
  2. Hard to tell without seeing the negatives in person, but those look more like dust or debris embedded in the emulsion than flaws in the emulsion due to processing.
    Check the negatives with a loupe or other magnifier, especially from an angle in bright light.
    Check the chemicals for debris or incompletely dissolved materials. If you're on rural or well water in limestone basins, mineral deposits can occasionally be a problem - especially in areas with oil/gas drilling and fracking. If you're using water filters, check to be sure filter particulates aren't getting into the solution - that happened to me several years ago and ruined several negatives before I realized the problem was dust from the filters. Thoroughly rinsing out the filters solved that problem.
  3. The constant problem with darkroom photography is cleanliness. It's a never ending battle that you can't actually win. But if you obsess about it, and become a disciplined darkroom worker, you can reduce dirt on film to very small levels indeed.
    I spent the better part of a year in a war on dirt in my own darkroom and workflow. I was able to reduce the dirt on my negs by 90% or more. It all comes down to a few basic principles.
    First, never use tap water. For anything. Use only steam distilled water. Use it for mixing all your chems, for diluting, and, yes, for washing. Not just your film, but any equipment that comes in contact with your film. In my case this means the Jobo 3010 drum I use to process my 5x4 film.
    Never let any equipment dry right side up where dust can fall in it. This includes all your graduates, trays, drums, film and print washers, all of it. Protect everything, immediately as soon as it gets its final rinse in cleaning. In distilled water of course. :)
    Never reuse any chemicals. Everything one shot. Yes, this includes stop bath. And it emphatically includes fixer. There's a good chance what the OP is showing is precipitate from fixing that got on the film by reusing the fixer. Yes, this in general means that you'll be throwing away fixer that's not completely exhausted (hint -- use it for fixing paper). OTOH, you won't be spotting as much. And fixer is cheap compared to the time it takes to do a good job spotting. Just sayin'. And it goes without saying that you should *never* reuse photoflow. Never.
    Now the worst one -- clean your darkroom. I'm talking washing the ceiling. And the walls. And the undersides of shelves. Top, bottom, and sides of every surface. At least every six months. More if you're doing more work. It's amazing how much dust can cling to a ceiling. In a room that's already the cleanest room in the house!
    Do those things and you'll be amazed at how clean your negatives become. Beware letting your guard down though. You drop your vigilance, your dust will come right back. Again, just sayin'.
  4. Fist you should examine the negatives using a magnifier, minimum power is 10x. Hold the negatives up to the light to examine by transmitted light then hold the negatives so the light is reflected from the films surface. Close examination will reveal if the spots due a contaminate sitting on the surface blister or a crater etc.
    Assuming they are bubbles and or blisters: The developer is alkaline pH 12 (about). The stop bath is dilute acetic acid (vinegar). Both the stop and the fixer are acid as the fixer contains acetic acid. If the stop or the fix are too strong (acid), trapped developer in the film emulsion will liberate carbon dioxide gas as the developer is neutralized. The gas that is generated can cause the emulsion to blister.
    The generation a carbon dioxide is accelerated by high temperatures. Sometimes the blisters break through to the surface; sometimes they are imbedded in the emulsion.
    A rinse is water preceding the stop is a good preventive. Reviewing the action of the stop bath. Most common developers are alkaline. If the pH of next bath is acid, all development is arrested. A stop bath is desirable to arrest development quickly if the development time is short (under 5 minutes). If the development time is greater than 5 minutes, rapid arresting of the developing action is not of great importance. In other words, a water rinse substituted has merit if the developing time is protracted.
    Any residual development will be completely arrested in the fixer, which is acid. The fix contains the same acid and the stop. The stop serves two purposes, immediately arrest development and prolongs the life of the fix bath by neutralizing and acidifying developer carryover. The bottom line is, in a home darkroom, prolonging the life of the fixer bath is generally not an issue.
    Recheck the mixing instructions that came with you stop to see if your working solution strength is too strong. Consider replacing the stop with a water rinse. Try and keep all fluids, including water baths and washing at around 68⁰F / 20⁰C. (cool) and all within ± 5⁰F / 3⁰C.
  5. Thanks guys. I appreciate what you are saying but my dust regime is pretty good. I do reuse stopbath and fixer. I don't reuse developer except microphen stock. The thing is.... this problem has only happened twice, both with TMY and TMax dev. The day before I developed the TMY, I was developing Neopan 400 in D76, using the same stopbath and fixer and drying the negs in the same dust sealed room, without any sign of spotty negs. It just seems too much of a coincidence that the both times it happened it was with the same film/dev combination.
  6. If you're certain it's not dust, check the chemicals for undissolved particles. Check your water supply too.
  7. If it is only happening to TMY then it is almost certainly a water issue. Wash with distilled water and will likey just go away.
  8. I've certainly had silver particle problems with fixer. Changed brands and that went away. But filtering through a coffee filter can clean up fixer.
    If washing again with distilled water doesn't clean up the specks, that may be it. The silver particles generally get "into" the emulsion.
  9. It happens to me when I use a combination of Foma100 and wd2d+. This combination is super sensitive and I have to be "pure" on how I develop.
    If it were an issue with crap in the fixer, it would happen to all the film.
  10. I respect Bruce's reply and thoroughness of procedure but I have a simpler system that works for me. One shot for most of your chems including fixer. For film drying I use a spray bottle set to mist and spray the drying room down before hanging the film. This removes any dust in the air. As far as distilled I only use it with my final photoflow rinse which works fine and keeps my films spot free.
  11. Thanks again for everyone's input. The thing to remember is that I use about half dozen different types of film and four different developers with the same stopbath, same fixer and a demineralised final rinse for all. Its only the TMax 400/TMax dev combo that gives me a problem. Its been suggested that a presoak might help so I'll give that a try. It may be that the TMax developer has gone off. The bottle has been open for 2 years but I've used less than half as I only use it for pushes. I might try it with another film type.

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