Re: Monochromatic Noise
Posted: 2012-07-08T11:44:24-07:00
OK. I figured out how to do monochromatic noise. You have to separate channels and use the same seed on all channels and then combine. But note you need to be sure to use -set colorspace RGB so that the channels are kept as non-linear rather than as linear grayscale. Otherwise, the result is too dark
convert zelda3.png -set colorspace RGB -separate -seed 1000 -attenuate 1 +noise gaussian -combine zelda_gaussian_mono_1a.png
or
convert zelda3.png -set colorspace RGB -separate -seed 1000 -attenuate 1 +noise gaussian -combine -colorspace RGB zelda_gaussian_mono_1b.png
P.S.:
This also works, but is ever so slightly darker. So I am not sure which is the better approach.
convert zelda3.png -separate -seed 1000 -attenuate 1 +noise gaussian -combine -colorspace sRGB zelda_gaussian_1d.png
convert zelda3.png -set colorspace RGB -separate -seed 1000 -attenuate 1 +noise gaussian -combine zelda_gaussian_mono_1a.png
or
convert zelda3.png -set colorspace RGB -separate -seed 1000 -attenuate 1 +noise gaussian -combine -colorspace RGB zelda_gaussian_mono_1b.png
P.S.:
This also works, but is ever so slightly darker. So I am not sure which is the better approach.
convert zelda3.png -separate -seed 1000 -attenuate 1 +noise gaussian -combine -colorspace sRGB zelda_gaussian_1d.png