K Szczech
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Well, cameras also have non-linear characteristics which is some sort of tone mapping.Movies have done fine without tone-mapping (as we know it in games/software). Photography has been fine without tone-mapping. All we need is proper exposure and lighting setups.
I once posted a comparison between linear color space and non-linear tone mapping:
As you say, introducing non-linear tone mapping decreases contrast and decreases saturation of image, but it also preserves proper tone of image in bright areas. Look at that green strip on the sky when using linear color space.
It's caused by green and blue color components to be allready at maximum possible to display values (255) while red component still needs to catch up.
Just like you can get oversteer with sound, you can get overbright with image, but the problem with image is that it has 3 independent components. When one of them is oversteered and others are not, then one of them is not properly represented while other two are. This means that actual visible color will be different than it should be.
Tone mapping tends to bend the color curve near maximum values and therefore reduces this effect.
For the same reason sky on photo you pasted is completely white. In reality you would be able to see it's blue tone no matter the brightness.
Contrast in reality can be huge sometimes and there are only 3 ways of representing this on computer monitor:
- darken entire image so that colors can fit into limited display range (we wouldn't like to drive on dark circuits wouldn't we?)
- leave the image oversteered and with erroneus colors near overbrights
- apply some kind of non-linear function that will squeeze that contrast into display range, sacrificing some contrast and saturation
Well, optimally game should allow all three
If your display monitor can handle high contrast, then you may let the game render darker images and just brighten up your monitor. You sacrifice some color precision, but it may still work out well.
With other display monitors some people would prefer 2nd or 3rd option.
Personally I'd go for tone mapping. Contrast and brightness can be subjective and you can get used to them while some artifacts like green strip on the sky will always look bad.
An interesting option would be to perform tone mapping and then use gamma correction and postprocessing to increase contrast and saturation.
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