Kell Factor

Kell factor is a parameter used to determine the effective resolution of a discrete display device. The number was first measured in 1934 by RCA engineer Raymond D. Kell and his associates. It has no fixed value, but is usually taken to be about 0.7, for electron gun scanning. Kell originally defined this as 0.64, and then later revised it to about 0.85. The number can be higher than 0.9, when fixed pixel scanning (e.g. CCD or CMOS) and fixed pixel displays (e.g. LCD or plasma) are used.
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