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Need your advice on a VW760ES

masodes

Standard Member
hi,

I have opportunity to buy a second hand vw760. Here are rgb balance charts and correlating calibration settings. Im concerned by the high values for gain and bias.
What do you think about? Normal?
What is your advice?

Thanks a lot
 

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Flambolt

Novice Member
Yes, the values are undoubtedly high, especially the bias setting. If you have red bias set to -11, you will (most likely) have a poor greyscale tracking near black. The gains are not as critical - but the high red gain, might lead to clipping. You can also see that red, takes of like a rocket after 90 ire.

Normally you would only make a minimal correction to the bias, observing the infuence on the steps near black, and then make any additionally needed corrections, using the Sony Projector Calibrator PRO software or Image Director.

I wouldn't worry about buying the projector based on these settings, they say nothing regarding the state of the unit - only that it has not been optimally calibrated ;0)

Any gammadrift, can easily be corrected using the Sony Projector Calibrator PRO software or Image Director.
 
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masodes

Standard Member
Yes, the values are undoubtedly high, especially the bias setting. If you have red bias set to -11, you will (most likely) have a poor greyscale tracking near black. The gains are not as critical - but the high red gain, might lead to clipping. You can also see that red, takes of like a rocket after 90 ire.

Normally you would only make a minimal correction to the bias, observing the infuence on the steps near black, and then make any additionally needed corrections, using the Sony Projector Calibrator PRO software or Image Director.

I wouldn't worry about buying the projector based on these settings, they say nothing regarding the state of the unit - only that it has not been optimally calibrated ;0)

Any gammadrift, can easily be corrected using the Sony Projector Calibrator PRO software or Image Director.

Thank you very much for your help! Sounds promising.

Gammadrift can be corrected, but what's about rising black floor or shrinking contrast ratio?

I read that one should level 100IRE with gain settings and then use PCP software downwards?
 

Flambolt

Novice Member
Yes, i would largely agree to this method. Since any shift in greyscale is almost always in the direction of blue (with a Sony projector), and the low IRE being worse than the top IRE, i would recommend focusing mostly on 100 IRE when using the gains. You can however make small adjustments to the bias, just to get red and green to track better - but be careful.

You need precise contrast measurements to determine if a unit has suffered a loss in contrast, and these are often hard to come by.
Unless the unit was measured when new, and then re-measured (after optimally calibrating the unit), then any measurement done now, will only reflect the performance with the applied settings, and current level of drift.

Hope this makes sense :)
 
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