Help with developing

greenspun.com : LUSENET : B&W Photo - Film & Processing : One Thread

I use HP4 plus 125 and last few times I have proccessed the film it starts getting small blisters while drying which turn to spots when the film is dry.....my guess is that I am fixing it longer than necessary, I use Lauder chemicals "Rapid fixer" and am wondering if I am right. If this is the case, will reducing the time of fixing stop it or is there another culprit to these blister? Any help will be greatly appreciated.

-- Nauman Saghir (Nsaghir@hotmail.com), December 13, 2000

Answers

Are you properly diluting the fixer? The fixer normally comes as a concentrate, and you need to mix it with water.

Make sure that all the steps from developer to wash are at the same temperature. Temperature changes can lead to funny emulsion things.

What about your stop bath? Is it properly diluted? I actually mix my stop for film at 1/2 strength. Too strong a stop with some developers can lead to pin holes from gas formation in the emulsion. You don't even really need stop, plain water will work about as well. Try it.

-- Terry Carraway (TCarraway@compuserve.com), December 14, 2000.


Are you sure these are really "blisters"? Is the emulsion coming off at these points? Could they simply be water spots? Do you use a wetting agent before drying the film? Try a drop of Edwal LFN (low foam wetting agent) in 500ml of distilled water as a final rinse before hanging them to dry.

-- Ed Buffaloe (edb@unblinkingeye.com), December 14, 2000.

For a long time I used tap water to wash my film, and then I would follow that up with a final 30 - 60 second rinse in a wetting agent mixed with distilled water. My negatives had no problems with water spots. Several months ago the water somehow changed and spots began to appear. What I do now is wash the film initially in tap water and then complete the last third of the wash cycle, letting the film sit for 2 - 3 minutes between changes, using distilled water followed by the wetting agent. This has dramatically reduced the spots on my negatives.

-- Christopher Hargens (ldmr@cruzio.com), December 14, 2000.

Do the spots stay a pinky/grey colour? If, so then I'd think your fixing method isn't working correctly... check dilution against manufacturers recommendation and try more regular and vigorous agitation to ensure film gets even treatment.

-- Nigel Smith (nlandgl@unite.com.au), December 14, 2000.

Moderation questions? read the FAQ