Inter‐instrument color measurement errors of up to 2 CIELAB units are typically introduced in the process of numerically integrating spectrophotometric data to obtain tristimulus values. These errors arise partly from inadequacies in the definition of the tristimulus values themselves, but mainly from failing to take into account the effect the instrument function has on the spectrophotometric data. Through using precise definition of the tristimulus values and through using source‐observer weighting tables tailored to each specific instrument, it is practical to reduce this component of colorimetric error to less than 0.1 CIELAB unit for spectrophotometers with bandwidths up to 20 nm.

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Spin-lattice relaxation has been monitored via pulse techniques in polycrystalline dimethyl sulfone (DMS) and a 1:1 polycrystalline solution of DMS in the perdeutero analogue. The temperature range covered for DMS was between −90.1 and +75.8°C, while for the 1:1 solution it was between −111.4 and +72.8°C. The relaxation was found to be consistently nonexponential, with exponential relaxation being approached at the lowest temperature. The extent of the nonexponentiality is intermediate between that expected from the effects of cross correlations and that expected from a simple averaging of the exponential behavior of randomly oriented single crystals. A parameter δ=τnull/Tlav is introduced, which may be used to judge the extent to which cross correlations are increasing the observed nonexponentiality beyond that expected from a simple averaging of the exponential behavior of randomly oriented single crystals. Further, it is suggested, in situations where cross correlations do not completely determine the nonexponentiality, that the initial slopes of the decay plots be used to determine correlation times for methyl reorientation since these initial slopes are independent of cross correlation effects. Correlation times for methyl reorientation in DMS have been determined and yield an activation energy of 4.22±0.07 kcal/mole.

Through the use of an efficient design and a newly available sphere coating material, a simple, passive, sturdy averaging sphere was made that operates effectively over the wavelength range from 200 nm to 2000 nm. Data are reported for a sphere of this type in which the sphere transmittance is 0.32 at 200 nm and rises rapidly to near the maximum theoretical value of 0.56 over the remainder of the wavelength range. The several orders of magnitude reduction in error due to beam displacement more than compensate the slight reduction in signal for many spectrophotometric and radiometric applications.

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