Methods and apparatus for color calibration and verification

A method of calibrating a color measuring instrument with a color standard and verifying said color standard and said calibration, said method comprising:

• providing a color standard having a surface with at least a first region and a second region, wherein said first region has a first color characterized by a first predetermined coloration having premeasured color measurement value(s), and wherein said second region is photosensitive so that it changes color in a known way when exposed to a predetermined dose of light, the change in color distinguishing the so exposed color standard from a color standard that has not been so exposed;
• calibrating said instrument with said color standard;
• exposing at least said second region with light;
• and
• verifying that said color standard used in calibration is an authorized color standard of a predetermined specification and that the calibration of the color measurement instrument has achieved predetermined specified results.

A method for calibration of a color measuring instrument and verification of the calibration using a color calibration and verification apparatus, said apparatus comprising:

• a color standard having a substantially opaque surface with at least two different colors arranged for simultaneous color measurement to sequentially calibrate the instrument with first predetermined color measurement value(s) of the color standard and verify the calibration with at least second and different predetermined color measurement value(s) of the color standard, and
• variance means to provide said first and second different color measurement values, said variance means being selected from the group consisting of:
• (1) sequential inclusion and exclusion of predetermined color measurement value(s) of a portion of said colors, (2) sequential exclusion and inclusion of predetermined color measurement value(s) of a portion of said colors, and (3) sequential exposure of photosensitive paper or material which provides at least one of said colors or portion of at least one of said colors, said photosensitive paper or material being capable of changing color in a known way when exposed to a predetermined dose of light, the chance in color distinguishing the so exposed color standard from a color standard that has not been so exposed, said method comprising the steps of:
• calibrating said instrument with said first predetermined color measurement value(s) of the color standard;
• causing the variance means to provide at least second and different predetermined color measurement value(s) of the color standard;
• and
• verifying the calibration of the color measurement instrument with said at least second and different predetermined color measurement value(s) of the color standard.

A method for calibrating a color measuring instrument and verifying the calibration of said instrument, said method comprising:

• (a) providing a color standard having a substantially opaque surface with at least two different colors arranged for simultaneous color measurement;
• (b) sequentially calibrating the instrument with first predetermined color measurement value(s) of the color standard and verifying the calibration with at least second and different predetermined color measurement value(s) of the color standard;
• (c) providing variance means to provide said first and second different color measurement values, said variance means being selected from the group consisting of:
• (1) sequential inclusion and exclusion of at least the predetermined color measurement value(s) of a portion of said colors, (2) sequential exclusion and inclusion of at least the predetermined color measurement value(s) of the portion of said colors, and (3) sequential exposure of photosensitive paper or material which provides at least one of said colors or region or portion of said colors, said photosensitive paper or material being capable of changing color in a known way when exposed to a predetermined dose of light, the chance in color distinguishing the so exposed color standard from a color standard that has not been so exposed;
• (d) calibrating said instrument with said first predetermined color measurement value(s) of the color standard;
• (e) causing the variance means to provide at least second and different predetermined color measurement value(s) of the color standard;
• and
• (f) verifying the calibration of the color measurement instrument with said at least second and different predetermined color measurement value(s) of the color standard.

A color calibration and verification apparatus for calibration of a color measuring instrument and verification of the calibration, said apparatus comprising:

• a color standard having a substantially opaque surface with at least two different colors arranged for simultaneous color measurement to sequentially calibrate the instrument with first predetermined color measurement value(s) of the color standard and verify the calibration with at least second and different predetermined color measurement value(s) of the color standard;
• and
• variance means to provide said first and at least second different color measurement values, said variance means being selected from the group consisting of:
• (1) means for sequential inclusion and exclusion of predetermined color measurement value(s) of a portion of said colors, (2) means for sequential exclusion and inclusion of predetermined color measurement value(s) of a portion of said colors, and (3) means for sequential exposure of photosensitive paper or material which provides at least one of said colors or portion of at least one of said colors, said photosensitive paper or material being capable of changing color in a known way when exposed to a predetermined dose of light, the change in color distinguishing the so exposed color standard from a color standard that has not been so exposed.