Biological analogs of RGB pixilation yield white coloration in giant clams

Giant clams utilize two mechanisms to produce white colora- tion analogous to that from RGB pixelated electro-optical displays. In the first, the mixed reflection from tight clusters of differently colored iridescent cells yields white. In the second, cells containing subcellular Bragg reflectors with heterogeneous lamellar spacings reflect multiple wavelengths to appear white at the macroscopic scale. Both mechanisms represent unique systems of structural color that produce white by color mixing. 

Ghoshal, A., Eck, E. and Morse, D. E.
Optica
Volume: 3
Number: 1
Pages: 108-111
Date: January, 2016
ICB Affiliated Authors: Daniel E Morse