Photocolorimetry refers to the science of measuring and analyzing the color of a substance based on its interaction with light. Synonyms for this term include spectrophotometry, colorimetry, and photometry. Spectrophotometry involves analyzing the intensity and wavelength of light absorbed by a substance. Colorimetry is the measurement of color perception in which the properties of light are evaluated by observing the differences between the photometric quantities of two differently colored physical samples. Photometry involves measuring the brightness or intensity of light, typically using specialized instruments designed for this purpose. These terms are often used interchangeably depending on the specifics of the situation at hand.