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Greyscale Comparisons
on colour sets
T
he block on the left below shows monitor RGB red, green and blue in brightnesses 255, 192, 128 and 64 (e.g. RGB 255,0,0 192,0,0, 128,0,0 and 64,0,0 for red). The block on the right shows these converted to greyscale by the formula that is selected from the options panel: this page is interactive, you can click in the radio buttons and checkboxes.
The numbers in the monocrome squares show the brightness level 0-255 by the:
SELECTED BRIGHTNESS CALCULATION FORMULA
gamma
squared
linear
gamma exponent
sRGB
YIQ
CIE XYZ
DCs
Lgtness
Average
Exponent if blank or zero is 2.4 For details of what the calculations mean see:
Formulas for Calculating Pixel Brightness
130
96
62
28
220
165
110
54
70
50
30
10
N
ote that some formulas are more convincing than others when looked at this way. The linear formulas (which includes Lightness and Average under every condition) are especially weak.
omit brightness values
And there are the print colours: Yellow, Cyan, Magenta, also in brightnesses 255,255 192,192 128,128 64,64 (e.g. yellow 255 is made up of 255 red and 255 green).
248
187
124
62
228
171
114
56
145
108
70
32
And then there are twelve hues separated on the color circles by 30°, i.e on the HSV or HSB colour space they are hues 0, 30, 60, 90, 120, 150, 180, 210, 240, 270, 300 and 330°. At any given brightness level each of these should look about equally bright. Some brightness calculation formulas work better than others with this. See too my page Equivalent Colour Brightnesses.
RGB 255, 140, 140
RGB 255, 145, 36
RGB 179, 179, 0
RGB 98, 196, 0
RGB 0, 201, 0
RGB 0, 201, 101
RGB 0, 196, 196
RGB 110, 182, 255
RGB 168, 168, 255
RGB 205, 156, 255
RGB 255, 125, 255
RGB 255, 135, 195
The RGB values are in the rightmost boxes
brightness level
This page last updated 10 October 2024