Metrology:.

In T'Hutch's original metrology was established at Bill Voglesong's PSI Associates company, to incorporate the numerical analysis procedures used for calculating the integral of the spectral products, p and weighted spectral power distribution Pt, which are standard procedures specified by the American Society for Quality Control (ASQC).

At In T'Hutch, the primary instrument is a X-Rite 938, S/N 000102, which has a geometry of 0/45. The reflectances are traced to BCRA tile set MCSL-56 using the spectral reflectances certified by Munsell Color Science Laboratory at the Rochester Institute of Technology, and thus NIST. The differences between the MCSL calibration and In T'Hutch instruments averages 0.4ΔE, with a maximum of 0.9. Uncertainty is 0.64%

Typical measurements are made with the illuminant D50, 2° Observer. Other illuminants may be incorporated at the customer's specification, even spherical with special order.

Secondary Instrument is a X-Rite 530 Spectrophotometer, cross-

calibrated to the 938.

Note that all data published with In T'Hutch reference materials are calculated from spectral data.

X-Rite 938 (SN000102) Specification:

Bandpass: ~10nm

Wavelength Range: 400-700nm

Recording Interval: 10nm

Accuracy: 0.4 mean Delta E(ab) for 12 calibrated ceramic tiles

Uncertainty: Wavelength (M0)

400 0.70%

500 0.57%

600 0.58%

700 0.59%

*Coverage Factor k=2

Please note that, although X-Rite has declared the 938 to be obsolete from their support, this instrument undergoes monthly reference checks to insure traceability to NIST through the RIT Munsell Color Laboratory measurements on In T'Hutch tileset.