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  1. #11
    RH Designs's Avatar
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    I would suggest setting a hard grade - 4 or 5 even. The Ilford head uses two lamps with green and blue filters, and our StopClock 500 controls these independently to produce a split-grade exposure. It's not possible to get white light from the Ilford head (unless you remove the filters altogether). We haven't actually tried graded papers but given that they are mostly blue-sensitive, setting a hard grade will minimise the use of the green lamp. Maybe PE can offer some more advice given the above product information, although I entirely agree that it's largely pointless to use any filters for graded paper if you have a white-light source. Ron, do you think the green sensitivity is generally sufficient to make it worthwhile using the green lamp as well as the blue?
    Regards,
    Richard.

    RH Designs - My Photography

  2. #12
    Fintan's Avatar
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    Thanks Richard, I appreciate your advice.

    Fintan

  3. #13
    Jim Noel's Avatar
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    Graded papers are blue sensitive only. Set your head so that it projects only blue light.
    [FONT=Comic Sans MS]Films NOT Dead - Just getting fixed![/FONT]

  4. #14
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    There are two factors involved if you are using a photometer to set the exposure: the color sensitivity of the paper and the color sensitivity of the meter. My advice is to set the light's color at white and calibrate the meter so that you know the exposure values (light * time) that produce the steps of a projection step wedge. The paper does not have a sharply defined band pass. Limiting the color of light to blue will cut off some of the light to which the paper is sensitive without any benefit to the purpose at hand. Exposing with or without a filter will have no effect on contrast. Just remember that the object, if you're going to use a meter, is to "teach" your meter to see as the paper does.
    Gadget Gainer

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