Gain and Bias settings? - AVS Forum
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post #1 of 5 Old 10-08-2012, 09:04 PM - Thread Starter
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Been a while since i messed with my TV settings. I was going back and tweaking them after changing some stuff around and cant remember exactly what these settings did exactly. The Red, Green, and Blue Gain and Bias settings. I think the Gain control only goes to the negative range, up to about 20 or so, and the Bias option goes either + or - 10 either way. If i recall they are under either the grey scale, or white ballance section of the TV's options

Can anyone clarify me what the Bias and Gain settings do? I.e. What does cranking the Red bias down or up do, or dropping the Red Gain down? Specifically what the difference between the two is, because it seems like they adjust the amount of that color in the picture. Thanks
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post #2 of 5 Old 10-08-2012, 10:11 PM
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Gains are effectively RGB contrast controls.

Bias are RGB brightness controls.

You really can't adjust either without a meter. The human eye is extremely adaptive to the color of white (the brightest color, weather reddish or bluish, looks white), so you'll need something objective to adjust the controls.

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post #3 of 5 Old 10-08-2012, 10:20 PM
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Thanks for the response. Sorry I should have mentioned it earlier but all of these adjustments are being done using a meter and CalMAN. It is those readings that told me to bump up red and blue for grayscale but from what I have read some people say you should never increase it only decrease and that increasing it means the contrast isn't set right. However, like I said I believe it is at the right spot ad i start crushing colors if I go any higher. Any thoughts on why people say never to increase the gain/bias and if there are any exceptions to the rule?
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post #4 of 5 Old 10-08-2012, 10:34 PM
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Decreasing it is never wrong, you'll never cause clipping that way, which makes it a good rule of thumb.

Increasing can cause clipping, so if you increase you need to recheck contrast after you're done.

You can get good results either way as long as you understand how the controls interact.

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post #5 of 5 Old 10-09-2012, 07:52 AM
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Looks like I actually responded to the wrong thread (sorry OP!) but thanks for the response on both threads sotti - this makes good sense to me. No real problem with adjusting gains up for grayscale, provided you recheck to ensure you are not clipping white, and colors, and your luminance is where you want it. Correct?
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