Table 2.

Coloration metrics.

Name/description	Formula	Reference
	$C=\sqrt{L{M}^2+M{S}^2}$
	LM = B R − B G
	MS = B Y − B B
	where:
	$B_B=\frac{{\sum }_{\mathrm{400}}^{\mathrm{474}}Q(\lambda ,x)}{B}$
Chroma	$B_G=\frac{{\sum }_{\mathrm{475}}^{\mathrm{549}}Q(\lambda ,x)}{B}$	[35]
A measure of the “purity” or saturation of a colour; a function of how rapidly intensity changes with wavelength	$B_Y=\frac{{\sum }_{\mathrm{550}}^{\mathrm{624}}Q(\lambda ,x)}{B}$
	$B_R=\frac{{\sum }_{625}^{700}Q(\lambda ,x)}{B}$,
	$B=\sum _{400}^{700}Q(\lambda ,x)$
λP 50
Wavelength that divides the spectrum in two parts with equal spectral energy (i.e., the median of the cumulative distribution between 400–700 nm)	$\sum _{400}^{\lambda P_{50}}\hspace{0.17em}=\sum _{\lambda P_{50}}^{700}\hspace{0.17em}$	[33, 34]