As I understand it luminance (measured in Candela / m²) is a physical measure for the brightness perceived by the human eye. So the unit Candela already takes into account the biological response function of our retina -- it doesn't just measure total emitted light energy. Still, Candela / m² is not exactly proprtional to perceived (subjective) brightness + this discrepancy depends on the frequency spectrum of the presented light. And obviously this discrepancy will vary with different human observers. [Edit: And, as pointed out by Steven Kersting, subjective brightness is surely not proportional to Candela, but rather scales logarithmically due to Weber–Fechner].
With this info in mind, my question is as follows. I am interested in the perceived brightness of an average (or "standard") observer for a set of colors presented on a screen (defined as RGB triplets 0..255). I do have the luminance (Candela / m²) measurements for these colors for the screen of interest. Is it possible to estimate perceived brightness with this info for a standard observer (*)?
I also have the luminance measurements for each channel alone, i.e. when the RGP triplet was (50, 100, 70), I have the channel-wise luminance measurements for (50, 0, 0), (0, 100, 0) and (0, 0, 70). Not sure this is of help though.
Unfortunately, I don't have access to this screen anymore and thus can't do experiments.
(* standard observer referring to standardized observers as e.g. defined by the International Commission on Illumination, CIE: https://cie.co.at/publications/colorimetry-part-1-cie-standard-colorimetric-observers)
