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I would like to invert the values in my image in the compositor node, but as you can see from the output shown in the image below, the inverted image appears blown out. You can clearly see this in the almost fully white background.

I want to use the compositor to adjust image textures for pbr materials such as roughness and normal which should be set to non color data in the shader editor as well as base color and emission color which use sRGB. enter image description here

I wonder if it is the result of color space however I haven't found a combination that makes sense or works. You can see here my current settings for color management in Blender's render properties: enter image description here

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I believe the Invert node simply inverts the channels with 1 - channel. But as your input data is in sRGB, you need to remove the gamma curve before doing this linear operation and apply it afterwards again (note 0.455 in the image is actually 1/2.2 = 0.454545...):

enter image description here

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  • $\begingroup$ Thank you! What is the significance of the value 2.2? $\endgroup$
    – Zak Nelson
    Jul 28 at 17:23
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    $\begingroup$ It's the common gamma value used in most image file formats to map between linear and sRGB color space. There are plenty of resources if you search for Gamma correction. $\endgroup$
    – taiyo
    Jul 28 at 17:47
  • $\begingroup$ @ZakNelson could not edit my comment anymore. In short, the mapping is not linear but with an exponential function, and the exponent is called gamma. $\endgroup$
    – taiyo
    Jul 28 at 17:56
  • $\begingroup$ Thank you. I've marked this as the accepted answer. $\endgroup$
    – Zak Nelson
    Jul 28 at 17:58
  • $\begingroup$ Should I keep my view transform in the color management settings as Standard, rather than filmic? $\endgroup$
    – Zak Nelson
    Jul 28 at 18:51

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