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Why do I see 3 values for 75% of white? Same for 50% and many other values.

Yes there is a difference between each other, #C0C0C0 is (192, 192, 192), #BEBEBE is (190, 190, 190), #BFBFBF is (191, 191, 191), but why is it shown like this?

december color codes

percent of white color

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    Is you question literally why the RGB values are what they are? – Cai Aug 16 '16 at 15:33
  • Different color profile? – joojaa Aug 16 '16 at 15:35
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    You can not have a 75% white. White is white. – Rafael Aug 16 '16 at 18:53
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    The "74" is a red herring. All those swatches on the linked page that conform with that naming are based on CMYK where CMY=0 and K is variable. The naming is grey(100-K) and the RGB values are integer values R=G=B=(255*(100-K)) – Yorik Sep 1 '16 at 15:07
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    actually make that r=g=b=(255*(1.0-K)) – Yorik Sep 1 '16 at 16:20
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When you search for colors on a brightness percentage basis (HSL) 100% = rgb(255, 255, 255) which means each 1% = ~2.55rgb leaving color values in between that are more accurately defined using rgb and/or hex color codes. The lost values are most likely a bi-product of HSL models in web/software applications that attempt to visualize the color values for user convenience.

HSL and HSV are the two most common cylindrical-coordinate representations of points in an RGB color model... [HSL] representations are used widely in computer graphics, and one or the other of them is often more convenient than RGB, but both are also criticized for not adequately separating color-making attributes, or for their lack of perceptual uniformity.


Basically, not all rgb values are represented percentage-wise in HSL/HSV models.

Check Out the Wiki

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None of those colors are exactly 75% gray, because that precise shade cannot be exactly represented using the 3×8-bit RGB palette. Specifically, your colors are:

  • "gray" = #BEBEBE = rgb(190, 190, 190) = 190 / 255 ≈ 74.5% gray
  • "gray75" = #BFBFBF = rgb(191, 191, 191) = 191 / 255 ≈ 74.9% gray
  • "silver" = #C0C0C0 = rgb(192, 192, 192) = 192 / 255 ≈ 75.3% gray

The middle one, "gray75", is technically closest to 75% gray, as the name indicates, but the others differ from it by only 1 / 255 ≈ 0.4%. In practice, while that difference may be barely detectable by the human eye, if the two colors are juxtaposed on the same display, it's completely negligible compared to variations in display calibration, not to mention the perceptual differences due to ambient lighting. So in practice, it doesn't really matter which one you use — if you just see a gray box on the screen, there's no way you can possibly tell which one of those shades it is.

(Also, it may be worth noting that, because all standard RGB color spaces and display devices are perceptually non-linear, and have a display gamma greater than one, none of those shades are actually anywhere close to being 75% as luminous as pure white. On a typical computer monitor with γ ≈ 2.2, those shades of gray are actually only about 0.752.2 ≈ 53% as bright as pure white. Converting them to CMYK for printing will, of course, produce something completely different again. Fortunately, the human eye is pretty adaptive, so in practice, even fairly large differences in overall gamma are not very noticeable, as long as they're consistently applied to the entire image.)

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The reason there are multiple RGB values for the same CMYK color has to do with the color gamut that can be produced by each process. It's not that the 25% black screen converts differently (well it does, but that's a different lesson) but more that 25% black is the closest approximate match that CMYK can produce to match that RGB color.

Here is a link to a video that explains it decently. It's not the greatest video, but it gets the point across.

Color Gamut Video

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