seting curves endpoints in lab/Rgb

annacarinaannacarina Registered Users Posts: 6 Beginner grinner
edited July 25, 2006 in Finishing School
Hi. im trying to use/set Dan Mar. lightnees endpoints in RGB . curves. really thats not the problem. I set them to 97 and 6 but when i convert to lab i can still measure 100 and 0. why- dosent curves automatically clip the highlight and shadow when setting like this. i dont understand it. Yhanks for any advice. anna

Comments

  • Duffy PrattDuffy Pratt Registered Users Posts: 260 Major grins
    edited July 24, 2006
    annacarina wrote:
    Hi. im trying to use/set Dan Mar. lightnees endpoints in RGB . curves. really thats not the problem. I set them to 97 and 6 but when i convert to lab i can still measure 100 and 0. why- dosent curves automatically clip the highlight and shadow when setting like this. i dont understand it. Yhanks for any advice. anna

    It's not entirely clear what you are doing. Are you changing the inputs or the outputs?

    If you are setting an input of 97 to an output of 100 then you will be clipping anything that originally lay at 97-99. But the range of the picture after this change is still up to 100. Its just that anything that used to be at levels 97-100 is now set to 100.

    If you are setting an input of 100 to an output of 97, you are doing a contrast reducing move. Anything from 97 to 100 will now have a level of 97. This won't clip anything (in the sense of blowing highlights. Instead it will compress detail in the very high end. If you do this, and then convert to LAB, you will still have a curve that theoretically goes from 0-100, but there will be no information on points 98-100.

    I hope this helps.

    Duffy
  • annacarinaannacarina Registered Users Posts: 6 Beginner grinner
    edited July 25, 2006
    Duffy Pratt wrote:
    It's not entirely clear what you are doing. Are you changing the inputs or the outputs?

    If you are setting an input of 97 to an output of 100 then you will be clipping anything that originally lay at 97-99. But the range of the picture after this change is still up to 100. Its just that anything that used to be at levels 97-100 is now set to 100.

    If you are setting an input of 100 to an output of 97, you are doing a contrast reducing move. Anything from 97 to 100 will now have a level of 97. This won't clip anything (in the sense of blowing highlights. Instead it will compress detail in the very high end. If you do this, and then convert to LAB, you will still have a curve that theoretically goes from 0-100, but there will be no information on points 98-100.

    I hope this helps.

    Duffy

    Hi Duffy. first: Sorry for using the word clipping when not knowing the meaning. Yes im changing the input 100 to output 97.I understand what u are saying - thanks very much. regards anna
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