Madrigal Imaging MP-9 CRT projector Calibration

Calibration

By the standards of 9-inch CRT projectors, the gray-scale tracking of the Madrigal Imaging MP-9 (second sample) was superb at a relatively low light output of 7.1 foot-Lamberts. Increasing the Contrast level to produce a peak-white output of 10.4ft-L on a 7-foot-wide screen pushed the projector slightly beyond its linear operating range, but the degree of blooming was small and did not, in my judgment, significantly affect the MP-9's performance with typical video material. It did, however, slightly compromise the gray-scale tracking. Specifically, the blue tube began to lose its punch as the picture level increased above 85 IRE, resulting in a slight greenish-red shift. The degradation did not compromise the overall quality of the image, however. The color remained natural-looking, including flesh tones, and the shift would likely be visible by most viewers only in a side-by-side comparison. I do not, however, recommend that the MP-9 be used with a 1.3-gain screen wider than 7 feet, or a 1.0-gain screen wider than 6 feet. A screen with a gain higher than 1.3 will provide greater brightness, but at the costs of increased hot-spotting and reduced color accuracy. The latter, in particular, seems an odd compromise to make when outstanding color accuracy is a big part of the premium price you pay for an MP-9 in the first place.—TJN

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