## Introduction

In the previous post about my monitor, I used five colors: red, green, blue, white, and a pale purple. For each of them, I began by specifying RGB values… I used Digital color meter to find their XYZ values… and I demonstrated that the relationship was nonlinear when applied to the purple color.

The relationship was…

XYZ = M (RGB)^1.801

where M, however, is linear (a matrix).

I found the nonlinear part of the relationship from the following graph out of my ColorSync utility…