In preference dialog, there are several items with “dither”.
My question is that, what’s the meaning of “dither”?
And, is it the same meaning with the options of paintbrush “jitter” ?
Hi! Per the help manual, jitter is defined like this:
“Normally the brush draws a line by printing the brush marks close together. Adding jitter means that the brush prints are scattered along the line.”
Dithering is different. It’s the method used to reduce colors (like when indexing)
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“Dithering” here is applying a very low level noise. If you convert a 8-bit image to 32-bit, without dithering all the pixels that have the same value in the original image will end up with the exact same value in high-precision, and will react exactly the same to color changes, so you can still have banding because all these pixels will change together. Dithering makes all these pixels have slightly differing values, making gradients look more uniform.
In the Blend tool, “dithering” is about the same, the purpose is to avoid banding by avoiding simultaneous value changes in aligned pixels.
There is also a “dithering” in the conversion to indexed color, but it is more simulating the original color with a suitable pattern of pixels that use the colors in the color map.
See also Wikipedia
“Jitter” is just adding a “shake”.
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I get it.
Thank you.