I'm using ImageMagick-6.7.7-8-Q16-windows-static
The -colorspace Gray and -modulate 100,0 are both returning images that are much too dark.
s.
Greyscale too dark
Re: Greyscale too dark
Add -colorspace sRGB to your command line.
Re: Greyscale too dark
Hi, magick.
It worked well. Thanks for that; I can't see the rest of the site from where I am. A friend emails me:
"Auto convert images in the grayscale colorspace to sRGB"
from the changelog. Is this standard now?
s.
It worked well. Thanks for that; I can't see the rest of the site from where I am. A friend emails me:
"Auto convert images in the grayscale colorspace to sRGB"
from the changelog. Is this standard now?
s.
Re: Greyscale too dark
Got it. Thanks for your trouble.
s.
s.
Re: Greyscale too dark
Just a further question on the colour space theme.
This:
-evaluate PoissonNoise 2 -modulate 100,0
gives a very dark result; but this:
-random-threshold 0x100% -modulate 100,0
gives the correct result without any translation of the colour space.
Is the darkened output with -evaluate PoissonNoise 2 to be expected? (I know the degree of graininess is not the same, btw.)
s.
This:
-evaluate PoissonNoise 2 -modulate 100,0
gives a very dark result; but this:
-random-threshold 0x100% -modulate 100,0
gives the correct result without any translation of the colour space.
Is the darkened output with -evaluate PoissonNoise 2 to be expected? (I know the degree of graininess is not the same, btw.)
s.
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anthony
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Re: Greyscale too dark
You probably should convert the image to linear RGB colorspace first.
convert {input_image} -colorspace RGB ..... -colorspace sRGB {output_image}
The original problem is basically because auto-convert back to sRGB is turned off for grayscale images.
In IMv7 their is a definate difference between one channel grayscale, and multi-channel grayscale that
the auto-convert can make use of, but IMv6 does not have that difference (all images have at least 3 channels in memory).
convert {input_image} -colorspace RGB ..... -colorspace sRGB {output_image}
The original problem is basically because auto-convert back to sRGB is turned off for grayscale images.
In IMv7 their is a definate difference between one channel grayscale, and multi-channel grayscale that
the auto-convert can make use of, but IMv6 does not have that difference (all images have at least 3 channels in memory).
Anthony Thyssen -- Webmaster for ImageMagick Example Pages
https://imagemagick.org/Usage/
https://imagemagick.org/Usage/
Re: Greyscale too dark
What I'm querying is the inconsistency:
noise generation + desat = dark
random thesholding + desat = no change in gamma
-modulate 100,0 shouldn't involve colour space changes; it's just a desaturation op. Or so I thought.
s.
noise generation + desat = dark
random thesholding + desat = no change in gamma
-modulate 100,0 shouldn't involve colour space changes; it's just a desaturation op. Or so I thought.
s.