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  1. #61

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    Interesting Jason.....do you think that the light from a Gralab timer can fog film or paper?

  2. #62
    JBrunner's Avatar
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    Not in my experience, but my timer is out of line of sight (on a shelf with a lip above my trays). Exposure comes from both duration and intensity, so general speculations about abstract sources and situations aren't really useful.

    Testing is they key.
    That's just, like, my opinion, man...

  3. #63
    Ian Grant's Avatar
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    Light from timers can and will fog films, and I've seen them fog colour papers.

    A friend couldn't eliminate a very slight greenish cast when he began RA-4 printing, it was a tiny red LED on a timer that was the culprit. B&W paper is far more forgiving.

    Ian

  4. #64

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    Another question Jason...the point regarding light in the darkroom also involves where the light is coming from. IF the light is coming in from the bottom of the door, and is rather faint....since light travels in a straight line, if the light is not bouncing off of anything bright, how can such light affect film on a table some feet above and to the side of the bottom of the door? I agree that total darkness is to be preferred, but nevertheless, it appears that since light does travel in a straight line that the risk of fogging film above the light leak should be rather minimal, or zero. I also agree that tests might be done to be certain. Not debating that Ralph's method of sealing light leaks can relatively easily be accomplished....however, some here have pointed out that minimal light leaks have NOT affected their work, such work having been carried out in the same darkroom for many years. Those individuals find no compelling reason to change the design of their work space-and one would, it seems, have to accept their opinions. Obviously no absolute right and wrong with reference to the discussion at hand....if it "ain't broke, why fix it"?

  5. #65
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    Inverse square law. When people say some timer light is fogging their paper, the first thing to ask is where the timer is placed. If it's sitting on the paper then, well, duh.
    "Only dead fish follow the stream"

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  6. #66
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    Quote Originally Posted by Mahler_one View Post
    Another question Jason...the point regarding light in the darkroom also involves where the light is coming from. IF the light is coming in from the bottom of the door, and is rather faint....since light travels in a straight line, if the light is not bouncing off of anything bright, how can such light affect film on a table some feet above and to the side of the bottom of the door? I agree that total darkness is to be preferred, but nevertheless, it appears that since light does travel in a straight line that the risk of fogging film above the light leak should be rather minimal, or zero. I also agree that tests might be done to be certain. Not debating that Ralph's method of sealing light leaks can relatively easily be accomplished....however, some here have pointed out that minimal light leaks have NOT affected their work, such work having been carried out in the same darkroom for many years. Those individuals find no compelling reason to change the design of their work space-and one would, it seems, have to accept their opinions. Obviously no absolute right and wrong with reference to the discussion at hand....if it "ain't broke, why fix it"?
    Again a hypothetical. Too many variables. Even if I was present in the room I couldn't really tell you. Testing is the key. Working in a leaky darkroom and thinking that the leaks have no effect is much different than testing and knowing. Many a print lacks some of the subtle brilliance it could have, particularly in the very highest values, because of that kind of assumption (the assumption that there is no effect), and the photographer doesn't know the difference (perhaps for even for years) because he/she doesn't know the difference, but it can be the difference between a "10" and a print that goes to "11". I can't think of a single reason not to check, except for a lazy contempt for ones own work or sheer hard-headedness.
    Last edited by JBrunner; 01-11-2010 at 12:59 PM. Click to view previous post history.
    That's just, like, my opinion, man...

  7. #67
    jp498's Avatar
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    Quote Originally Posted by Mahler_one View Post
    Another question Jason...the point regarding light in the darkroom also involves where the light is coming from. IF the light is coming in from the bottom of the door, and is rather faint....since light travels in a straight line, if the light is not bouncing off of anything bright, how can such light affect film on a table some feet above and to the side of the bottom of the door? I agree that total darkness is to be preferred, but nevertheless, it appears that since light does travel in a straight line that the risk of fogging film above the light leak should be rather minimal, or zero.
    Different Jason.. If you look down, and see light on your floor surface or on your shoes, from the leak at the bottom of the door, then light IS INDEED bouncing up to your eyes, which is further away than the film. Anything you see as illuminated is sending light in your direction.

    If you are loading a 35mm roll onto a reel at waist level, the film could be twice as close to the floor as your eye, and gets 4x as much light as your eye, due to the inverse square rule.

    Now, I know I can load a roll of iso400 onto a reel and put it in the tank very quickly and won't have any fogging even if light is leaking in. I'm sure I've loaded at least a thousand rolls over two decades. However, I still like it to be really dark. What if I knocked off the table the top of my tank? I could spend several minutes feeling around in the dark for it, and I don't want my film to suffer in the process.

  8. #68
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    Quote Originally Posted by jp498 View Post
    ...Now, I know I can load a roll of iso400 onto a reel and put it in the tank very quickly and won't have any fogging even if light is leaking in...

    Seriously, how do you know? Have you checked? Or is it just something you are printing through without knowing it is there? Film is less critical about overall fog because you can print through it, having a base+fog level to begin with even under perfect circumstance, so my real point is directed towards printing, but this "snip" I have inflicted on Jason's post (apologies) illustrates my point quite well.

    Nice to see another Jason!
    Last edited by JBrunner; 01-11-2010 at 01:24 PM. Click to view previous post history.
    That's just, like, my opinion, man...

  9. #69
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    Quote Originally Posted by Sirius Glass View Post
    More more for the list.

    If the number of rods and cones were increased in our eyes, we would not see any better because the evolution of the resolution of the eye stopped when the evolution got to the diffraction limit of the eye.

    Steve
    Not sure about that.

    More cones might help. I don't think my eyes are diffraction limited at f/2.

    Not that I'm complaining or arguing with my maker, but...
    Regards

    Ralph W. Lambrecht
    www.darkroomagic.comrorrlambrec@ymail.com[/URL]
    www.waybeyondmonochrome.com

  10. #70
    keithwms's Avatar
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    I don't see what diffraction limit has to do with light sensitivity nor the number of receptors. the receptors aren't close-packed in a Bayer grid or something, they have an unusual distribution (hence blind spots). What we see and how sensitively we see it depends very much on the angle at which we look. E.g. optimal scotopic sensitivity is not head-on, this is well known to observational astronomers.

    Now, there is a correlation between the diffraction limit and the size of the photoreceptors in the eye: different animals have different sized receptors. But the spectral sensitivity of the individual receptors... the quantum efficiency, if you will.... is a different topic.
    "Only dead fish follow the stream"

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