Xenon short-arc lamp: Difference between revisions

Xenon short-arc lamp (view source)

328 bytes added , 17 February 2019

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 ===Measuring Luminance===
-When properly aligned, the brightness should be 16 [[foot lamberts]] +/- 2 at the center of the screen with no more than 25% drop off at the corners, in compliance with [[Society of Motion Picture and Television Engineers|SMPTE]] specifications.
+The [[Society of Motion Picture and Television Engineers|SMPTE]] specification is 16fL ([[foot lamberts]]) with uniform illumination across the projected area without film in the projector (open gate). Because spherical widescreen formats (1.66:1, 1.85:1) are the least light efficient, and 1.37:1 and Scope are more light efficient, you can split the difference with 15fL for 1.85:1 and 17fL for [[Cinemascope]].
+If you’re checking luminance through the port glass with your meter subtract 1~2fL. It’s always best to take your final readings in the auditorium itself.
 ==Aging==