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posterize
How can I find out the formula used by “posterize” to integrate a broad range of wavelengths (i.e. dark red, red and orange) to a narrow range (red only)? Is there a reference for this function?
posterize
"So when two “posterized levels” are specified, what determines light orange to be posturized to yellow and darker orange to become red?"
If the green channel is more than 128 (50%) then it will be rounded up to 255, producing red+green=yellow (0xFFFF00). If the green channel is less than 128 then it will be rounded down to 0, producing pure red (0xFF0000).
"And what determines that very light orange will be eliminated?"
If the red channel is below 128 (50%) and the green channel is below 128 then both will be rounded down to 0, producing black (0x000000).
what determines light orange to be posturized to yellow and darker orange to become red?
So when two “posterized levels” are specified, what determines light orange to be posturized to yellow and darker orange to become red? And what determines that very light orange will be eliminated?
posterize
The "Posterize levels" parameter specifies how many levels of color each of the red, blue, and green channels can have. Each channel of the input color is rounded to the nearest match of those levels. For example, if you specify two posterize levels then each channel can be either 0 or 255; resulting in one of eight possible colors for the pixel (0x000000, 0x0000FF, 0x00FF00, 0x00FFFF, 0xFF0000, 0xFF00FF, 0xFFFF00, or 0xFFFFFF).
If you specify three levels then each channel can have one of the values 0, 128, or 255. This results in up to 27 different colors. (The number of colors is equal to the cube of the number of posterize levels.)
Posterize levels
The "Posterize levels" parameter specifies how many levels of color each of the red, blue, and green channels can have. Each channel of the input color is rounded to the nearest match of those levels. For example, if you specify two posterize levels then each channel can be either 0 or 255; resulting in one of eight possible colors for the pixel (0x000000, 0x0000FF, 0x00FF00, 0x00FFFF, 0xFF0000, 0xFF00FF, 0xFFFF00, or 0xFFFFFF).
If you specify three levels then each channel can have one of the values 0, 128, or 255. This results in up to 27 different colors. (The number of colors is equal to the cube of the number of posterize levels.)
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