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Thread: what are the RGB values for an 18% gray?

  1. #1

    Default what are the RGB values for an 18% gray?

    Does anyone know what are the RGB values for 18% gray? Is it R:128, G:128, B:128?

    thanx!!

  2. #2

    Default Re: what are the RGB values for an 18% gray?

    In RGB it's 128128128, but for reflectance it's 117.
    Alpha

  3. #3

    Default Re: what are the RGB values for an 18% gray?

    18% Gray = R:224 G:224 B:224

  4. #4

    Default Re: what are the RGB values for an 18% gray?

    Quote Originally Posted by Enchanted View Post
    18% Gray = R:224 G:224 B:224
    It's not linear.

    (117 / 255)^2.2 = 0.18

  5. #5
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    Default Re: what are the RGB values for an 18% gray?

    Quote Originally Posted by grantyale View Post
    It's not linear.

    (117 / 255)^2.2 = 0.18
    In sRGB, it's closer to 118. sRGB doesn't use a simple power law and gamma=2.2 is only an approximation. To get a more accurate approximation, you can dither 64.46% pixels with a value of 118 and the remaining 35.54% with a value of 117.

  6. #6
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    Default Re: what are the RGB values for an 18% gray?

    All the given advice is far too "chim". Is there a more simplified explanation that can be understood by all laypersons?

  7. #7

    Default Re: what are the RGB values for an 18% gray?

    The reason it gets complicated, is that there is no simple three-values answer. It depends on the color profile you're working in. The RGB values of a given color varies between different color spaces (profiles).

  8. #8

    Default Re: what are the RGB values for an 18% gray?

    A lot of replies! Thanks every one for your input!

  9. #9

    Default Re: what are the RGB values for an 18% gray?

    RGB does not describe absolute colour... it is relative to the profile of your monitor, and to the profile of the image...

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