A colorimeter method and apparatus is described. The colorimeter includes a plurality of sensors/filter systems with non overlapping spectral responses, adequate for providing data capable of translation into standard coordinates system such as, CIE XYZ, CIE L*a*b*, or CIE Luv, as well as non-standard operable coordinate systems. The field of view of the colorimeter is chosen to closely track the response of the human eye using an optical path configured to select and limit the field of view in a manner that is insensitive to placement of the colorimeter on the source image. The optical path from the source image to the sensor is configured to select preferred light rays while rejecting undesirable light rays to maximize the signal/noise ratio. A rearward facing sensor channel is included to simultaneously measure ambient light impinging on the source image and feedback means to provide status and/or change of information.