System for distributing and controlling color reproduction at multiple sites

An apparatus for measuring the color reflected from a sample comprising:

• a light source for illuminating said sample;
• a line of light in which at least a part of said light represents light of one or more calibration references, and the remaining part of said line represents light received from said sample;
• and
• a spectrograph which receives said line of light and outputs spectra spatially related to points along said line, in which part of said spectra is related to said light of said calibration references and provides information for checking the calibration of the spectrograph.

An spectrograph for measuring the spectra of received illumination representing an image comprising:

• at least one reference providing light of one or more wavelengths;
• an array sensor having two axes in which one of said axes encodes a dimension of space in said image and the other of said axes encodes said spectra representative of points along said dimension of space;
• and
• optics for receiving and separating at the same time light from both the received illumination and said reference into spectral components, and imaging said spectral components onto said array sensor.

An apparatus adaptable for measurement of reflected, transmitted or emitted light of a sample, comprising:

• a dual beam spectrograph having first and second inputs, in which said spectrograph is capable of measuring said first and second inputs simultaneous with one another;
• a light source capable of illuminating a sample and capable of providing a reference for checking the wavelength calibration of said spectrograph;
• a first optical path for conveying said light of said source to said sample;
• a second optical path for conveying said light of said source to said first input of said spectrograph to provide a reference for said measurement;
• a third optical path for conveying said light reflected, transmitted or emitted from said sample to said second input of said spectrograph for analyzing the spectrum of the light received through said second input;
• and
• at least one sensor having spectral sensitivity at one or more wavelengths associated with said light source, in which said sensor is capable of receiving part of the light from the second optical path prior to reaching said first input, said sensor detects light independent of said spectrograph, and said sensor provides information for checking the calibration of the spectrograph.