[mark-r]

In 8-bit (per channel) color there is a standard for when the context is unspecified: sRGB. It was developed to match the characteristics of a "typical" display at the time of its creation. It won't be 100% accurate, but it represents the best you can assume. You're not forced to throw up your hands and give up.

[glkindlmann]

I see that https://en.wikipedia.org/wiki/SRGB#Translation_to_integers implies what I would call node-centered sampling ("standard" or "mid-tread" in the post), but are you aware of sRGB documentation that precisely specifies the quantization semantics?

Most of what I've read about sRGB focuses on the semantics of continuous (floating-point) R,G,B channels.