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luminance warping

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thomwill
luminance warping
on Jun 6, 2006 at 11:54:53 pm

i'm doing some animations with vertical lines of different colors moving across the screen over white, and when i preview them on an ntsc monitor i'm getting some warping of the image that seems to based on the lunimance values in different locations in the image. when its previews on an lcd monitor tho, the image is fine. adjusting the brightness and contrast settings on the monitor helps, but then the monitor is no longer calibrated properly. i've done broadcast-safe color correction and levels adjustments in both ae and fcp with no sucess. the problem seems to occurr with video as well. i've also tried different monitors as well as just a regular tv.

thanks for the help guys.

tom


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mark Suszko
Re: luminance warping
on Jun 10, 2006 at 5:08:32 pm

First of all, computer display LCD's and TV monitor CRT's cannot be compared directly, they are very different things.

Doesn't sound like you're luminance safe yet, nor chrominance. Do you have/use actual scopes on this, or are you getting the levels information somewhere else?

Quick test: apply a 50% gray over the entire clip, see if the playback behaves better. If so, your levels were still too high.

You may already have done this, but check if you are using zero or seven point five IRE for the black level, then re-check your brightest whites are touching 100 IRE units.

I have one monitor in my bay that's slowly going bad, and it will easily distort when white levels are at or over 100 IRE. If that monitor is acting wonky during a playback or digitizing session, I know for sure the source is too hot, and the scopes confirm this.


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thomwill
Re: luminance warping
on Jun 10, 2006 at 6:58:30 pm

all the levels are within the safe range, both luminance and chroma, and they appear fine on the scope and waveform. they gray had some effect, but it didn't correct the problem. thanks for the suggestions. maybe the monitor is just going bad.

KNIFE TO THE EYE!


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mark Suszko
Re: luminance warping
on Jun 11, 2006 at 3:17:19 am

What effect exactly DID it have?

BOOT TO THE HEAD!
:-)


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