Part 1. Basics of color perception

The way we see color from a painting is complex and involves the biology of the eye, the properties of light, and the properties of the pigment in the paint and it cannot be understood with any of the three left out. This first part covers the eye and our perception of light as color. The ways of describing and measuring color set out here are used in the rest of the paper.

The paint examples throughout come from measurements. Golden has published the reflectance of 78 of its Heavy Body acrylics straight from the tube [24], and Okumura, at the Rochester Institute of Technology, measured 26 matching colors from Golden’s Matte Fluid line mixed with more and more white [59]. Those 26 are the calibrated paints of these notes. Most mixtures shown here are computed from them with a model of how paint handles light, built on Okumura’s measurements and explained in Section 2.6; the other 52 paints appear only as the colors Golden measured.

The lessons in this part

• 1.1 The light spectrum
• 1.2 The three kinds of cone
• 1.3 The opponent process
• 1.4 Metamers
• 1.5 Adaptation
• 1.6 The six attributes of color
• 1.7 Color spaces, and CIELAB in particular
• 1.8 What a gamut is

Sources

[24] Golden Artist Colors, Inc., spectral reflectance data for 78 Heavy Body acrylics (10 mil wet drawdowns over a white Leneta card, D65, \(10\degree\) observer, 400–700 nm), published by A. Glassner and E. Haines, Golden Paint Spectra, https://www.realtimerendering.com/golden.html, 2025.

[59] Y. Okumura, Developing a Spectral and Colorimetric Database of Artist Paint Materials, M.S. thesis, Rochester Institute of Technology, 2005, https://repository.rit.edu/theses/4892.