Colorimetry
From The Glossary of Digital Photography
(1) The use of a colorimeter to determine the color value of a physical color sample. (2) The science of converting colors to numerical color values. See also colorimeter

ONLINE GLOSSARY OF DIGITAL PHOTOGRAPY
(1) The use of a colorimeter to determine the color value of a physical color sample. (2) The science of converting colors to numerical color values. See also colorimeter