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This article describes how to convert from the sRGB color space, not RGB.

sRGB like Lab* is device independent so a transformation between the two is possible.

RGB on the other hand is device dependent, and would therefore require a device ICC Profile to convert to Lab*.

To be more specific, RGB is a color model, and sRGB is one of the color spaces that uses this model, alongside device-specific color spaces.

> RGB on the other hand is device dependent

No, it isn't. RGB is just a color model. You cannot convert between a color model and a color space any more than you can covert between float and Euros.

In order to convert between RGB and L*a*b you need a color space. That could be an ICC profile, sure, but it could also just be any well defined color space like sRGB, Display P3, or bt2020

It seems like you two agree on everything except what "device dependence" means...? GP acknowledged that there is no direct conversion between RGB and Lab, distinguished RGB from sRGB (implying the former is not a colour space), and indicated that a colour space like sRGB does solve the problem (since TFA is about using it to solve the problem).

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