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Thread: Sun exposure...

  1. #11

    Join Date
    Apr 2006
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    Quote Originally Posted by Guillaume Zuili View Post
    I did a 16x20 test today. Very weird day with the sun diffused by a lot of smog. Amazing how fast the exposure was. 5 minutes top and for sure it was over exposed.
    Was it because of this huge diffused light ?
    5 minutes is quite long for Southern California, I think. I expose my kallitypes which are of similar speed to VDB I guess for only about 1 minute in Tucson, AZ . It must be this smog but it had to blocked UV.

    Jan

  2. #12

    Join Date
    Jun 2007
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    nyc
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    point source vs very large difuse source

    Quote Originally Posted by chrobry View Post
    5 minutes is quite long for Southern California, I think. I expose my kallitypes which are of similar speed to VDB I guess for only about 1 minute in Tucson, AZ . It must be this smog but it had to blocked UV.

    Jan
    i believe that the ususal cloudless conditions in az allow the original point source-the sun-to over ride any other considerations-the uninterupted power of the sun in your part of the world is both a blessing and a curse i think

    you dont mention where you position your frame-out in the open under the sun- or in open shade

    a reading of the literature available in english from 1800 on will give a foundation to understand the variables

    then we can discuss the uv blocking or passing of smog and other materials

    and the variables of the response of different lite sensitve materials to various proportions of visible and uv radiation

    the variables of the response to different colors of visible lite and the mixes and color temperatures

    point source vs large both difuse and collimated

    and so on and so on and scooby dooby doowah

    sometimes i wish i lived in az tho

    vaya con dios

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