light leak?

Discussion in 'The Darkroom' started by Allsmiles7282, Feb 24, 2005.

  1. Allsmiles7282

    Allsmiles7282 TPF Noob!

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    For all you darkroom experts out there, I have a question. I've been noticing lately that all of my prints are coming out very very grainy and I can't figure out why. I switched developing tanks and that is about when this problem started happening. I've used the same film as always and the same developer and fixer as always. Could it be that the new tank has a light leak somehow and is expoisng my film? If not, does anyone have any ideas as to what could be casuing this problem?

    Thanks so much! =)
     
  2. Rogue Monk

    Rogue Monk TPF Noob!

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    Wouldn't it leak if there was any gapping or cracks?

    Is there a way for you to do the development process in the dark?

    Alternately, you could buy on of those glowsticks (usually around $1 tops). Crack it and drop it in the tank. Cap the tank and take it into a dark room.

    The results of either test will tell you if its a light leak.
     
  3. oriecat

    oriecat work in progress

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    Do you agitate differently in the new tank? It doesn't seem to me that a light leak would cause grain, but streaks on the film. But I don't claim to know...
     
  4. ksmattfish

    ksmattfish Now 100% DC - not as cool as I once was, but still

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    A light leak would show up as dark patches on your negs. If you are positive that you haven't adjusted developer strength, time, and temp, then I would consider that the new tank (is it a different brand/model?) allows for increased flow around the film, and maybe you need to alter your agitation.
     
  5. Allsmiles7282

    Allsmiles7282 TPF Noob!

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    hmmm, I didn't really think there is a light leak because my neg are consistant, no dark pathches or streaks. So maybe you guys are on to something with the agitation. So if it is grainy, does that mean that I am agitating too much or too little?

    I appreciate your help SO much! =)
     
  6. Hertz van Rental

    Hertz van Rental TPF Noob!

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    Grain will increase for one of two reasons.
    -overdevelopment
    -reticulation

    If the film is overdeveloped, grain size increases but this also results in increased density on the neg. Overdevelopment can result from increasing the developer concentration, increasing the development time, increasing the agitation, increasing the temperature. Small variations in these are cumulative so a small increase in agitation and temp can result in far more overdevelopment than you would think. Usually, though, you have them working opposite ways and they cancel out.

    Micro-reticulation (I have posted about this before) is caused by thermal shock. If you plunge a film that you have processed at 20C into iced or hot water the emulsion contracts and produces a result like baked earth in a drought.
    At less extremes of temperature (sometimes only 1 or 2 degrees) the effect happens at a much reduced scale. The result is a microscopic crazing of the emulsion that looks, even under enlargement, like bad grain. There is no increase in neg density.

    If your negs are of similar density to your earlier ones then I would suspect micro-reticulation. In 90% of 'grain' cases this is the culprit.
    If you have changed tanks your new one may be more thermally efficient and so loose heat quicker. Your dev - and therefore film - may be several degrees lower when you put in stop/fix at 20C and this is enough to cause low-level micro-reticulation and look like increased grain. The same thing will happen if the ambient temperature in the room is higher than the developer. The temperature of the film will increase above that of the stop/fix and thermal shock will result.

    The Cure: A band from the 80's that was part of the New Ro...
    Sorry!
    Process using a water jacket (stick the tank in a big bucket of water at 20C) and monitor with a mercury photo thermometer. Keep all temperatures within 1C of each other. This includes the wash water!
    Timings should be precise (within 10 secs). Measurements for mixing should be as precise as you can manage.
    Agitation should be precise and consistent.
    If you control all aspects of processing precisely you can then start making small changes in one aspect at a time to get optimum processing.
    This will deal with micro-reticulation and over/under development.
    I would suspect, though, that a water jacket should solve your problem.
     
  7. solo

    solo TPF Noob!

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    hey,, i have read ur problem, and it happend to me once... those grains needs more fixing... i meant, u have to put ur negative in fixer more than the time u had put it in... that was what happend with me one time... so check ur negative.
     
  8. panchromatic

    panchromatic TPF Noob!

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    perhaps you could also expore the fact that maybe your camera isn't exposing correctly? Underexposure perhaps?

    Just a thought, worth checking.

    --Ryan
     

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what if there is a small light leak in your darkroom