Relationships of spot RGB scores (i.e. dots' color) with their spectral measures and pigmentation indices.

<p>(A) The two brown spectral variables, (B) the two principal components obtained from the three brown eggshell pigmentation indices. We increased the transparency of points (alpha = 200) to improve the visibility of the 474 eggs from 42 clutches in (B). We measured the spectral coloration of the spots on a subsample of 31 eggs from 30 clutches in (A). The brown spots become browner (in response to digital saturation and hue) and darker (digital brightness) as spectral brightness decreases (A) and PC1 values increase (B). There are not such relationships with spectral chroma (A) and PC2 values (B).</p>