some 'mistakes' I would like to learn from.

Discussion in 'B&W: Film, Paper, Chemistry' started by Quinten, Jun 4, 2005.

  1. Quinten

    Quinten Member

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    I've only been serious with developing for a short while and some 'mistakes' I don't understand repeat themselves. Maybe one of you know what happends:

    -purple spots on the negatives after drying, even after extensive washing. (can the water I use to wash be to cold to be effective?)

    -some negative turn out really flat, even the ilford text on the edges next too the exposed frames are nearly transparant, feels like the emulsion is completely washed of since it's not over exposing that creates this.

    Maybe the next two questions are related to the filmback of my camera, It's an A12 for hasselblad.

    -on many negs the left edges next to (and possible a bit on) the exposed squares are slightly darkened, seems there was light on it.

    -The first and the last two frames on a roll are completely 'overexposed' but again also next to the exposed frame, than there is a sudden halt. (a straght line after wich everything looks normal, sometimes in the middle of a frame.)
    In case it was only one side this could make sense, but it is two sides. (this happends about one every 4 films, while I use the same equipment the same way.

    and my appologies for all these simple questions, I am just to damm curious:wink:

    cheers!
     
  2. gnashings

    gnashings Inactive

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    Hi Quinten,

    I am a relative beginner myself, so I will qualify my response with that statement. I have had issues of a purple cast on my negatives, and from my research, this is what I gathered:

    No one seems to agree on what causes it 100%. The main school of thought is that it is a washing issue. Careful and thorough washing seems to be the answer. I found that with certain types of fixer I have had this problem more than with the Ilford Rapid Fix that I mainly use (Kodak recommends a herdener fixer for their B&W film, and I have had more purple cast with their fixer, even though I used the hypo clean afterwards).

    The issue is, you mention spots... that is strange. It seems to be a case of some kind of impurity in your process - either the water, the containers you use? Perhaps some cross-contaminations from other chemicals? DO you use any detergent to wash out your tanks and reels? I strictly do not, but you probably already know this.

    Everything else seems like a light leak - I know you say its not consistent, but Ihad a troublesome light leak that seemed to be coming on and off seemingly without any pattern. Turns out it was very slight, and in low light or indoors, I had no problems, the minute the camera went out at high noon or any bright, sunny day, I had issues. New foam fixed the problem (it was a 35 mm SLR). I am not fmiliar enough with the mechanicals of a hassy to be sure, but I wold look into it. Do you use a dark slide whenver handling your backs? I hope I don't offend you by my comments - I am not implying any incompetence - just going through alist of those obvious things that I know we all forget at one time or another, I know I have! Best luck,

    Peter.

    One more thing - what type of reels do you use? I use the plastic Pattersons, and I find that I have to be particularily careful when cleaning them, as they tend to accumulate liquid in the grooves, and I found that I had some "artifacts" on the edges of my negs until I made sure the reels were thoroughly clean and dry before each use.
     
  3. Quinten

    Quinten Member

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    Hi Peter, thanks for your reply. I'll certainly look into some of the things you mentioned. (like the washing process)

    But what do you mean with a dark slide?

    thanks,
    Quinten
     
  4. gnashings

    gnashings Inactive

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    I know that on the removeable backs, there is a metal plate that slides in (between the camera body and film back), protecting the front of the back (wow, that is a weird sentence...) from light exposure. I don't recall, not having had a hassy in hand in over a decade and a half(!), but I know that on some medium format cameras, like the Mamiya RB67, you can't remove the back without putting the dark slide in place. This may be a source of some of your troubles.

    It is the proper term, "dark slide", as far as I know - soemone please correct me if I am givin Quinten the wrong info here.
     
  5. Nick Zentena

    Nick Zentena Member

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    If you've got spots I'd be suprised if it's washing. Cold water takes longer to wash but if you wash long enough it'll do the trick.

    The film sounds underdeveloped if the Ilford writing is off. Unless Ilford had a problem with a batch of film but that's very unlikely.

    Light leaks for the other problems.
     
  6. Quinten

    Quinten Member

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    I think I get it, it's just the metal plate you slide into the filmback before removing it right? I have it in the back when I am not taking a picture, so it must happen somewhere once that slide is out.

    I'll do some tests with the lenscap on and long exposures etc.
     
  7. rogueish

    rogueish Member

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    Light leaks I would say is the problem. I am going through the same thing with my RB67 back. My problem is the cover does not close properly (there is some play).
    As for the faint negs I would have to agree with Nick Z. Sounds like under developing. Also try to be consistant with you temperatures. If your dev. is 20 degrees, make sure your stop,fix and wash water is also 20 D, +or- 3. Most of the lititure I have read say +-5 degrees but I try to match everything as close as possible usually within 1 d.
    2 days ago I adjusted my dev.time as the room was warmer than normal. According to the Ilford temp adjusting table, I was to dev for 5 minutes at 23c instead of 6.5 minutes at 20c. I must have read the table wrong as my negs can out quite underdev. Don't know if I can use them, it's pretty bad.
    If your gettting purple spots perhaps your fixer is not thourghly mixed? (I doubt this, but one never knows).
     
  8. Quinten

    Quinten Member

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    do fixer temps and times matter?

    I am pretty accurate with the tempratures during development, as well as for the time, but does it matter what temp the stop bath and fixer are? I must say I don't pay to much attention to the time the fixer is in. As for stop baths and washing it's very hard to store so much water as needed for those things and bring at 20c. The water that comes out of my tap is about 12c

    thanks
     
  9. fhovie

    fhovie Subscriber

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    The risk is reticulation (grain clumping and emulsion cracking) the window of temperature change is 4deg F. If all your solutions are within 4deg F of eachother, you will not need to worry about this kind of damage. I have made this mistake myself and know these figures are correct from experience. - When the tap water for wash is far off (which it usually is here in Southern California) I fill the tank with tempered water and then let the wash water mix with and replace the water in the tank allowing for a gradual change. This has always worked for me as well.
     
  10. blansky

    blansky Subscriber

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    As for the light leaks on the Hasselblad backs what you need is to have the back serviced. There is a gasket that goes under the black plate that he back's serial number is on that need replacing. You can do it yourself but probably having it done is a better option, so that the rest of the back can be looked at as well.

    To check for the light leak, take out the film magazine and the dark slide. Hold the back at eye level with the flat part facing up and the winding crank by your nose. Looking straight along down the flat part of the back, lift the end farthest from your nose up just very slightly. Slide the dark slide in about half an inch, then back out. Where the light leak probably is, is where the dark slide first shows up under the black plate (with the serial number on it). The dark slide has slowly worn away the gasket and now you have a light leak. If you hold it to the light you will probably see some daylight where the darkslide slides in.

    If this is too confusing PMail me.

    Michael
     
  11. Tom Hoskinson

    Tom Hoskinson Member

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    What film are you using when you experience these purple spots?

    Colored residues are often caused by the incomplete removal of sensitizing dye during the fixing and washing process. Tabular grain films seem particularly prone to this.

    To remove these dye residues, I recommend the use of a non-hardening rapid fixer (like one of Ilford's, for example). Use of a post fixing bath, which can be either a 20 - 30 gram/liter solution of sodium sulfite or one of the proprietary Hypo Clearing Agents, is often helpful.
     
  12. Woolliscroft

    Woolliscroft Member

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    I agree with Tom. Might the spots just be incomplete fixing? I tend to find anyway, that T-max and Delta type films benefit from longer fixing than the instructions state. It seems to add a bit more bite to the contrast. I agree the faint negs sound like under development. If it was underexposure the maker's name and frame numbers would come up normal. As for washing water temperature. To avoid any danger of reticulation you can still drop the temp dramatically, but you need to do it very slowly. I fill the tank with water at 20c then run the hose very slowly for a few minutes until the tank drops to the temperature of the tap water and only then run it at normal speed. I give a final wash with a bit of wetting agent in water that has been twice through a chemical filter to remove chlorine, lime etc, again at tap temperature, which by then is what the film has got used to.

    David.
     
  13. jjstafford

    jjstafford Inactive

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    Given the clues my guess for the OP: Underdevelopment due to developer improperly mixed - water too cold to disolve so that it has precipitates in bottom of jug.

    Spots possibly due to bubbles from not rapping the tank.

    An aside: tabular films are very hard on fixer. It exhausts faster.
     
  14. Tom Hoskinson

    Tom Hoskinson Member

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    My own results agree. My practice is to test samples of the film I am working with in the fixer to determine the clearing time and fixing time required.

    I take a piece of exposed and undeveloped film, record the fixer temperature and place the film in the fixer, with agitation (room lights on) and record the amount of time required for the film to become transparent. I double the clearing time to determine the amount of fixing time for that film.
     
  15. Quinten

    Quinten Member

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    Thanks for the tips lads.

    I am not sure how I recognise a tubulair film but I shoot with APX100 and Tmax, I've only had purple spots on the APX once after fixing 9 Tmax films with the same fixer. (I change the fixer after ten films)
    So I supose the Tmax is a tubulair film since that's the one being sensetive to the spots. I am using agfafix but will give the non hardening fixer one of you sugested a try.

    Though I think the temprature is the most likely cause for the purple spots, since I wash this cold.

    Michael: Your test already gave me the answer without doing it, I thought the leaks came from a bit of play between the back and the camera but since the exposure on the negs is always at the left it's more than likely the place where the slide goes in. I'll have it replaced.


    Thanks for all sugestions, I've got some things to work with now.

    cheers!
     
  16. Woolliscroft

    Woolliscroft Member

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    I do that too. I usually cut the narrow bit off the leader as I load the spiral and then fix that. It also gives you a measure of the state of a particular batch of fix. When the time starts to increase, it's time to mix another batch. Tabular films = T-max and Delta. Possibly others, but they are the ones I use.

    Do you rap the tank after agitation to get rid of bubbles? I tend to bang it down twice on the sink after each aggitation and you still need to do that while fixing.

    David.
     
  17. gnashings

    gnashings Inactive

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    yes, I didn't think of it earlier, but the temperatures of ALL your baths should be co-ordinated carefully. I have to admit, I am doing it the cheap way - I have a Wal-Mart thermometer that I put under the tap, check the temp, and then mix my chemicals once teh temp has stabilized.

    Like I said earlier, I have had problems with hardening fixers (Kodak), even after almost fanatical washing. My problems were, however, of a more consistent nature, ie. the whole negative had a purplish hue. The spots are the perplexing part. The upper recommended time for fixing in rapid fixer (Ilford) is 10 minutes - and I always tend to use that time with good results. Highly recommend the stuff.

    Also, the faint negs - could yo be more specific as to the nature of the "faintness"? Does it occur alone or always in tandem with the other problems?

    And I am glad i was not totally off the wall with my suggestions about your film back :smile:
     
  18. fhovie

    fhovie Subscriber

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    Tabular films include TMAX and Delta - The grain crystals are like flat little plateletts. Regular films have grain that is more 3 dimentional. The differences include; quicker contrast swings with changes in development time and smaller grain structure. I believe they are a development from color film inovations.