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Mt. Baker Research L.L.C. Tutorial
Diagnostic Procedures
The Diagnostic Tile Sets introduce color standards and procedures for diagnosing instrument errors. Diagnostic Tile Sets A and B each contain 16 color standards. Set A supports instrument testing and the assessment of inter-instrument agreement in a multi-instrument environment. Set B enables licensed users of Set A and CyberChrome's OnColor Profiler® software to upgrade to profiling and color-management.
The color standards in Diagnostic Tile Set A were selected to meet the following criteria: (1) Span the complete photometric range. (2) Span the widest possible high-chroma gamut in CIELAB color space. (3) Include only high quality reduced translucency standards.
Partial List of Supported Tests
- Instrument Validation. For this test the color standards included in Diagnostic Tile Set A must be pre-calibrated in the optical geometries of interest. After the user measures spectral reflectance factors ("SRF") with the test instrument, the data are returned to Mt. Baker Research for diagnostic analysis. (Note: Mt. Baker Research supports certified traceable calibrations in 3 optical geometries.)
- Absolute Accuracy. To characterize the absolute spectrophotometric accuracy, the SRF data from the validation test may be compared with data measured at NRC or NIST for similar color standards. (Note: At present this test is supported for the (0°/45°) and the (45°/0°) bi-directional geometries.)
- Inter-laboratory Agreement. This test should be performed when the white calibration tile supplied with the test instrument is traceable to a standards laboratory other than NRC or NIST. This extension of the validation test measures differences in the photometric scales between the laboratories on which traceability is based. Based on recent tests at Mt. Baker Research, the magnitude of this error may exceed the statistical uncertainty of the measured SRF values.
- Instrument Revalidation. Repeating the validation test provides a basis for tracking instrument performance and for checking the user's procedures for storing and maintaining the color standards.
- White Calibration Tile. If the white calibration tile supplied with the test instrument is translucent, significant measurement errors may occur. Provided that LAV and VSAV sample ports are available, Diagnostic Tile Set A may be used to diagnose this problem.
- Translucency Sensitivity. Diagnostic Tile Set A set may be used to measure the sensitivity of the test instrument to SRF errors that result from lateral diffusion. This test requires the use of LAV and VSAV sample ports.
- OnColor Profiler®. In a multi-instrument environment color management by means of profiling may improve inter-instrument agreement. Profiling may be accomplished using the combined color standards in Diagnostic Tile Sets A and B together with CyberChrome's OnColor Profiler® software.
Linked Resources
- The instruction manual for the Diagnostic Tile Sets contains referenced background information about translucency. It also presents typical spectral reflectance factors in 3 optical geometries together with procedures for testing, validating and color managing spectrophotometers.
- CyberChrome's Color QC and Matching blog presents useful articles about measuring color and color managing spectrophotometers.
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