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  1. #41
    MattKing's Avatar
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    Ted:

    I wouldn't recommend replacing 30 second exposures with several (5?) 6 second bursts - the total exposure is very different, and you don't eliminate problems with negatives "popping"

    I haven't printed using a Durst enlarger for quite a long time, but IIRC Durst enlargers were quite good at preventing "popping, and I would think that the Ilford head would help prevent that too.

    As 2F/2F says, what does a loupe/magnifier tell you about the negative?
    Matt

    “Photography is a complex and fluid medium, and its many factors are not applied in simple sequence. Rather, the process may be likened to the art of the juggler in keeping many balls in the air at one time!”

    Ansel Adams, from the introduction to The Negative - The New Ansel Adams Photography Series / Book 2

  2. #42

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    Quote Originally Posted by heespharm View Post
    ted.. which durst enlarger do you have... i have both teh m301 and m606... I'VE had ur same exact problem and found the solution... for me I was using the red filter to get my focus... well it does defract the light and when using the red filter my pictures were slightly out of focus but looked fine in 5x7....
    This is an issue of how the human eye works. Patrick Gainer published a piece on this a while back in Photo Techniques magazine, IIRC. The bottom line is that it's best to focus using white or green light. Red light will cause you to focus incorrectly.

    FWIW, I've got a Philips PCS130/PCS150 enlarger, which uses three separate lights: red, green, and blue. I remembered this issue today during a printing session and I did a simple experiment: I focused using green light, as I usually do, then switched to blue light, then to red light. I noticed that the grain seemed just a little bit blurry when I switched to blue light, and using red light I couldn't make out grain at all, just a red blur. When I focused with red light and switched to green, again everything became a blur. I didn't bother making test prints when focused with each color, but maybe I should, just to check Gainer's article using a different technique. Because of the way the Philips enlarger is built, the effect I did observe cannot be accounted for by diffraction in the filters, since the filters are in the light path before the condensers, negative, or lens. This is purely an effect of how the human eye works.

  3. #43

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    Quote Originally Posted by srs5694 View Post
    This is an issue of how the human eye works. Patrick Gainer published a piece on this a while back in Photo Techniques magazine, IIRC. The bottom line is that it's best to focus using white or green light. Red light will cause you to focus incorrectly.

    FWIW, I've got a Philips PCS130/PCS150 enlarger, which uses three separate lights: red, green, and blue. I remembered this issue today during a printing session and I did a simple experiment: I focused using green light, as I usually do, then switched to blue light, then to red light. I noticed that the grain seemed just a little bit blurry when I switched to blue light, and using red light I couldn't make out grain at all, just a red blur. When I focused with red light and switched to green, again everything became a blur. I didn't bother making test prints when focused with each color, but maybe I should, just to check Gainer's article using a different technique. Because of the way the Philips enlarger is built, the effect I did observe cannot be accounted for by diffraction in the filters, since the filters are in the light path before the condensers, negative, or lens. This is purely an effect of how the human eye works.
    I think it's rather how the lens on your enlarger works.

    Focussing with green light helps because we are most sensitive to green. A focus shift in the eyes because of changing wavelength is accomodated by a focus shift by our eyes.

    A trick your enlarger lens cannot perform.
    Shows why colour correction is important in a lens that's used for B&W too.

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