Light Fall-off? I'm clueless...

Discussion in 'Medium Format' started by justin_stott, May 8, 2008.

  1. I just got out of the darkroom printing some pictures I took of my new dog at the beach. I noticed something going on that I had not picked up on before...The pictures look like I have something like light fall-off on the sides of the frame. I didn't pick up on it before but I've had this happen on prints in the past, but only occasionally, usually in bright sunlight. I have never had this with indoor ambient light or studio flash. I am using a Hasselblad 500CM with 80mm planar lens and a beseler dichro 67S2 enlarger. Picture of just dog is Ilford Delta 100 dog and boy are on Delta 400. I didn't write down exposure info, but I was hand holding so I was probably using a medium large aperture and a pretty fast shutter speed. http://www.photo.net/photo/7242661 http://www.photo.net/photo/7242657 I couldn't find anything searching...I would appreciate any help. Thanks! Justin Stott
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  2. Is it on the neg or just on the print? It's not light falloff as that would be uniform. If it's on the neg then check the film back or inside the camera body for blockage. If it's just on the print then my guess is that something is blocking the light in your bellows. Check inside your enlarger (bellows, carrier, dichro head) to see if anything is blocking light from getting to the enlarger lens, and check the lens too.
     
  3. That looks like a loose wrap of film to me on the finished roll. Light gets into the loose wrap (at the top and bottom of the finished film roll) and overexposes portions of the frame. It's definitely not light fall-off, because that would be dark areas.<P>Check to see if there are darker areas on the negative that correspond to the light areas in the negative.
     
  4. I guess it could also be light leaks in your film back as well.
     
  5. You are right Evan , looks like loose wrapped film in bright light....
     
  6. I've found a couple of other threads on this, I'm thinking it must be a light leak. The problem is evident on the negative but it is on the edges that face the next exposure, not along the top and bottom, so I don't think it's loose wraping. I guess it's in for a $ervice. BTW those two exposures are from two different backs. Must be time to call in the pros!

    Thanks for your help!
     
  7. This is the opposite to light "fall off", which is experienced as dark vignetting, achieved either deliberately with a mask, accidental with the wrong lens shade, or with very short focal length /wide angle lenses that usually require a centre filter to balance the exposure.

    And my first thought too, is a loose wrapping of the film. If the fogging exposure goes right to the edge of the film, and between frames it is loose wrap on the roll. If the fog is within the image frame only, it is most likely loose magazine, but certainly a camera fault. But it would most likely vary from frame to frame, and would indicate a VERY loose magazine. Which I have to say, this does not resemble, at least from my experience.

    Can you quickly scan a strip of film to show us?
     
  8. It looks like a developer problem. It could be under-agitation, exhausted, contaminated, or a combination. Try another roll with fresh developer, clean reels, and invert your tank once per second, every 30 seconds while in the developer.
     
  9. "...invert your tank once per second, every 30 seconds while in the developer." Sorry... That should be "...invert your tank once per second, for 5 seconds, every 30 seconds while in the developer."
     
  10. Thanks for your responses...

    I don't have a good scanner, so the actual pictures are not quite as bad as the scans look, the gradient is smoother and not quite as pronounced.

    Fog is restricted to the image frame only, and I only get it when I'm shooting in bright light, so I think it's sounding more like a leak.

    I used HC-110 mixed with distilled water as a one shot developer for both of the rolls, agitating my standard 20 seconds per minute, 10 inversions twist and tap gently, for standard developing times. I've never had issues with the developing before, and didn't have the problem with another roll of Delta 400 that was shot in a Holga and developed in the tank with the roll from the Hassie.

    I'm going to try to stop by my favorite camera store and let their B&W guy have a look, he does alot of Hasselblad stuff.

    Thanks alot,

    Justin
     
  11. Just a little update, I found the leak! In case anyone ever runs into this again, check to make sure that the mirror is locking up securely, my 500cm is a 1969 and I guess the spring that holds the mirror up just got a little floppy, it doesn't lock up securely and leaks light around the edge.
     

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