Video Asylum

Posted by kotches (R) on January 02, 2002 at 00:14:40

In Reply to: Why so? Biasing can help perceived black levels... posted by Halcyon on January 02, 2002 at 00:02:59:

Halcyon,

Assuming we're properly calibrated, I can think of a few reasons:

0) Any light source in the room would still get back onto the screen without all surfaces being completely absorbent. So now you've got some washed out coloration.

1) CRT projectors have no issues with black levels, so a bias light does nothing more than to decrease the apparent brightness level of a source that's already low output. So you get a decreased contrast ratio available by introducing ambient light.

2) Digital projectors generally have higher light outputs, and can utilize a gray screen to improve perceived black levels, without using a bias light. Once again reflections are the enemy, and you don't want any light getting reflected back into the screen.

Regards,