Plasma and DLP Grayscale Calibration

Nuno Santos

Active Member
Hi,

Yesterday I did some calibrations on a Panasonic plasma and a Sim2 DLP projector.

I managed to get a pretty acurate grayscale tracking of the plasma using spyder2 and Colorfacts. Afterwards I moved on to a DLP front projector (much daunting task :eek: ) and although the grayscale wizard of the CF6 indicated a flat grayscale tracking from 40-100 IRE (I was taking readings with the spyder2 about 30cm away from the screen and pointing towards the screen), the reverse gray ramps on DVE had a red tinge on it. I had to decrease red gain a little so that this pattern seemed "pure B&W".

Could it be that the spyder2 has acuracy troubles with DLP front projectors? Can I / should I place the device facing the projector? (or even nearer to the projector?).

I'm using 0-100 IRE windows (not fields). Should it be better for front projectors to use fields instead of windows?

Thank you in advance :thumbsup: .

Cheers,

Nuno Santos
 

Gordon @ Convergent AV

Distinguished Member
AVForums Sponsor
Nuno: Tr-stimulus devicescan be innacurate when used with devices that emit a spectrum of light that their filter set is not able to "filter" properly. It's quite possible that your results with the Sim2 are purely down to that.

You can probably point it at the projector but I wouldnt go too close as you may overload the sensor and get nonsense readings. Also, pointing at the pj will mean you have taken the room and screen out the equation, so it wont be quite as accurate.

Gordon
 

Nuno Santos

Active Member
Hi Gordon,

Thanks for your answer :thumbsup: .

Yesterday I tried to use the training meter option on Colorfacts and teached the spyder2 with Red, Green, Blue and white windows readings from the screen and then pointed the device at the PJ (still near the screen). I could take consistent readings from 20IRE upwards which I believe its fine.

Do you think this can be a good method to overcome the tristimulus lack of sensibility on lower IRE %'s? Would it be more acurate to place the spyder2 nearer to the PJ lens (eg midway)?

NS
 

IronBear

Active Member
Gordon @ Convergent AV said:
Nuno: Tr-stimulus devicescan be innacurate when used with devices that emit a spectrum of light that their filter set is not able to "filter" properly. It's quite possible that your results with the Sim2 are purely down to that.

You can probably point it at the projector but I wouldnt go too close as you may overload the sensor and get nonsense readings. Also, pointing at the pj will mean you have taken the room and screen out the equation, so it wont be quite as accurate.

Gordon
The Spyder2 takes quite a bit of light to overload (~7500 cd/m^2, IIRC), so do not be shy with getting it close to the projector.

Bill
 

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