I don't think Riot has image desaturation ability. But... Does desaturating images reduce file size ?
In my experience, image file sizes have increased after I used an image editor to desaturate them. Why?
I thought desaturation means removing colour data from an image, so logically file size should reduce.
Does desaturating images reduce file size ?
(4 posts) (2 voices)-
Posted 13 years ago #
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RIOT does not provide yet Saturation adjustment.
Saturation refers to color intensity. The colors are not removed, but their intensity is simply reduced. If the saturation is drastically reduced the image may compress better.
But you should ask yourself: why alter the colors of an image, especially if they look good that way ?
I tkink optimization should be lossless or close to lossless.
If you have an image with few colors try reducing the number of unique colors instead and choose a proper format. But don't exagerate because the image must be optimized not simplified.Posted 13 years ago # -
Thank you for replying.
When I reduce the number of image colours(e.g. from 256 to 128 colours), the image can get ugly due to "posterization"(the gaps left by the removed colours,I think).
So I wanted to rather desaturate, because in desaturation there is no posterization. But I was disappointed to see that desaturation increased file size ( and sometimes an over-saturated image is smaller than a desaturated one).
What do you mean by reducing "unique" colours? RIOT does not let me choose which colour to remove.
(There is also one problem: there are some software, like Game Maker 5, that seem to take a compressed image and decompress it again, increasing the file size. How can we avoid that? )Posted 13 years ago # -
Color quantization is not meant to produce posterized results. In fact, if your images get posterized, this means you are doing something wrong, apart from the situation when you want this to happen.
Don't try to reduce photos to 128 colors. Instead, reduce images which seem to have few colors as visual perception, but in reality are stored with a higher color depth. Color quantization is smart enough to keep only the most important colors - the most frequent ones.
So the thumb rules are:
1. use as many colors as you need, but choose a format like PNG or GIF for images with few perceptible colors
2. use JPEG for photos
3. use true color PNG if you want to keep the maximum quality of photos(There is also one problem: there are some software, like Game Maker 5, that seem to take a compressed image and decompress it again, increasing the file size. How can we avoid that? )
You can't avoid this but if you work with a lossless format like PNG you won't lose quality along the way also. JPEG looses quality at each re-compression.
Posted 13 years ago #
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