colorSpec (version 0.5-3)

theoreticalRGB: Theoretical RGB Cameras - BT.709.RGB and Adobe.RGB

Description

BT.709.RGB

a theoretical RGB responder to light. The 3 responsivity spectra are constructed so that the RGBs from this theoretical camera, when displayed on an sRGB display after correct EOCF adjustment, would emit light with the same XYZs as the captured scene (up to a constant multiple).

Adobe.RGB

a theoretical RGB responder to light. The 3 responsivity spectra are constructed so that the RGBs from this theoretical camera, when displayed on an Adobe RGB display after correct EOCF adjustment, would emit light with the same XYZs as the captured scene (up to a constant multiple).

Format

Both are colorSpec objects with quantity equal to 'power->electrical' and 3 spectra: r, g, and b. The wavelengths are 360 to 830 nm at 1 nm intervals.

Details

All responsitivity spectra are linear combinations of the spectra in xyz1931.1nm. These 2 theoretical cameras satisfy the Maxwell-Ives criterion by construction. The responsivities are scaled so the response to D65.1nm is RGB=(1,1,1). All spectra have negative lobes.

The BT.709 primaries and white point are the same as those of sRGB (though the EOCF functions are different). Adobe RGB and sRGB share the same Red, Blue, and White chromaticities, and only differ in the Green. This implies that for both cameras the Green output is 0 at Red and Blue, and 1 at White. This in turn implies that the Green output is identical for both cameras for all input spectra, and so the Green responsivity spectra are identical for both cameras.

References

Poynton, Charles. Digital Video and HD - Algorithms and Interfaces. Morgan Kaufmann. Second Edition. 2012. Figure 26.5 on page 302.

See Also

quantity, D65.1nm, xyz1931.1nm, vignette blueflame