Increase gamma by lowering brightness - AVS Forum | Home Theater Discussions And Reviews

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post #1 of 10 Old 02-02-2013, 04:34 AM - Thread Starter
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Just a general question really. Is it wise to usenthe brightness setting to increase gamma?
For example I have a Panasonic VT30. Using a pluge i have set the correct brightness level accordingly. However to calibrate to 2.28 which gives better image pop over 2.2 i have to lower the brightness setting by 5 clicks. The set itself has 10pt gamma settings but playing with these can lead to undesired screen artifacts. So the question is have i followed the correct process in which to increase gamma ?

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post #2 of 10 Old 02-02-2013, 04:48 AM
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You would be better served by posting that here:

http://www.avsforum.com/t/1408338/official-panasonic-vt50-owners-thread/9840#post_22913104

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post #3 of 10 Old 02-02-2013, 05:54 AM - Thread Starter
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Quote:
Originally Posted by Bond 007 View Post

You would be better served by posting that here:

http://www.avsforum.com/t/1408338/official-panasonic-vt50-owners-thread/9840#post_22913104

Why is that? Its the process im after clarification on regardless of brand.

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post #4 of 10 Old 02-02-2013, 06:04 AM
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I see. You are correct.

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post #5 of 10 Old 02-02-2013, 06:05 AM - Thread Starter
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Originally Posted by Bond 007 View Post

I see. You are correct.

Thank you sir!

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post #6 of 10 Old 02-02-2013, 06:45 AM
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I remember reading that brightness should be set correct using the proper pattern and shouldn't be altered to influence gamma. I'm sure someone with more knowledge than me will reply.

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post #7 of 10 Old 02-02-2013, 06:47 AM
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You should not use the brightness adjustment to change gamma. It will lead, in this case, to crushed blacks. You want to be able to see (or at least have the TV display, whether you will see it or not depends on lighting conditions, APL, distance, etc) all the picture content above black. Reducing the brightness to raise gamma will sink that pic detail down into the black.
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post #8 of 10 Old 02-02-2013, 07:52 AM - Thread Starter
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Quote:
Originally Posted by Chad B View Post

You should not use the brightness adjustment to change gamma. It will lead, in this case, to crushed blacks. You want to be able to see (or at least have the TV display, whether you will see it or not depends on lighting conditions, APL, distance, etc) all the picture content above black. Reducing the brightness to raise gamma will sink that pic detail down into the black.

Ok.

So how do i increase gamma without touching the brightness ?

Presumably the process then would be.

1. Set brightness using pluge.
2. Set target gamma in tv menu, ie 2.2, 2.4 etc.
3. Measure gamma from 0-100 lum.
4. Use 10pt gamma controls to fine tune to desired gamma level.

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post #9 of 10 Old 02-02-2013, 02:35 PM
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I would swap #2 and #1. Changing the TV menu gamma selection often necessitates recalibrating the brightness adjustment.
Your correct options for increasing gamma would be the 10 point control and the 2.2, 2.4 etc gamma selection.

You know, you should be able to avoid major artifacts from the 10 pt control on your VT30, even the EU model that is stuck in low panel brightness. The VT30 has some visible banding in a gradient grayscale ramp even in THX mode, which doesn't have a 10 point adjustment. Basically, any mode that is not calibrated way too blue to cover up the problems is going to have at least some artifacts in a gray ramp. Now, misadjustment of the 10 point controls will certainly add to the problem; however, careful and meticulous calibration of them should give you a decent result with minimal artifacts and banding. If you have access to 5% increment windows where you can read in between the 10 point adjustments, use that as a tool to minimize errors in between bands.
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post #10 of 10 Old 02-02-2013, 03:34 PM - Thread Starter
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Quote:
Originally Posted by Chad B View Post

I would swap #2 and #1. Changing the TV menu gamma selection often necessitates recalibrating the brightness adjustment.
Your correct options for increasing gamma would be the 10 point control and the 2.2, 2.4 etc gamma selection.

You know, you should be able to avoid major artifacts from the 10 pt control on your VT30, even the EU model that is stuck in low panel brightness. The VT30 has some visible banding in a gradient grayscale ramp even in THX mode, which doesn't have a 10 point adjustment. Basically, any mode that is not calibrated way too blue to cover up the problems is going to have at least some artifacts in a gray ramp. Now, misadjustment of the 10 point controls will certainly add to the problem; however, careful and meticulous calibration of them should give you a decent result with minimal artifacts and banding. If you have access to 5% increment windows where you can read in between the 10 point adjustments, use that as a tool to minimize errors in between bands.

Thank you for the in depth answer Chad. Sometimes these things can get a little confusing when youre learning! Cheers again. Have a great weekend.

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