Greyscale Calibration and Gamma

vincentfam · ‎12-22-2008

Greetings Colleagues from the Uverse universe:

I have returned to update you on my "Greyscale and Colour Calibration for Dummies" adventures and to seek your seasoned advice.

Pursuant to the "Greyscale and Colour Calibration for Dummies" website, and after carefully studying my panny's service menu and, of course, heeding your advice on the service menu, I gained enough courage to enter into the service menu domain and attempt the dreaded greyscale calibration, using an eyeone meter (the cheaper one), the free software, DVE calibration dvd, and a lot of patience.

Results = Very close to 6500K (initial measurements placed the calibration around 7500k color temperature), with DeltaE below 1.7 (except for 0IRE and 10IRE), using the custom mode setting on normal. The color is much better than pre-calibration.

Was I nervous? H*** yeah! But I accomplished what I set out to do. I still nonetheless agree with your advice that the service menu should not be entered unless you know what you are doing.

Is the picture perfect? Not exactly. The Gamma (whatever that is) is 1.8 on my Panasonic plasma without any ability to adjust it. Perfect gamma is 2.2. (You who read this message and do not comprehend the technical jargon need not worry or fret any further. The more you become interested in obtaining HDTV perfection, the more you will learn about the technical aspects of HDTV calibration).

I would appreciate it if you would offer your well reasoned advice on how I can get the Gamma from 1.8 to 2.2. My research of technical websites suggests that the panny's cinema mode will offer a higher gamma (which I will attempt later), but I am looking for an alternative solution for gamma perfection.

Any suggestions will be greatly appreciated.

Vincentfam, no longer the hermit.

Message Edited by vincentfam on 09-13-2009 09:14 AM

oz_1 · ‎10-25-2008

I thought Gamma was controlled by contrast setting so the limit to the setting is 1.8 .

SomeJoe7777 · ‎01-30-2008

No, gamma and contrast are separate adjustments. And yes, correct gamma is 2.2 for TVs.

A lot of LCD TVs (especially models a few years old or older) run into this problem. (Not because of age, but because the drive circuitry and panels have improved since them).

The only gamma adjustment you're likely to find is in the service menu, and even then you will probably need the service manual to figure out how to adjust it.

You might also check over at the AVS forums (www.avsforum.com) and do a search on your model number. You may find a thread for owners of that model that may have some information in it.

Poor gamma can destroy a good TV picture. Gamma is a measure of how fast the TV "comes out of black" as the brightness of the picture elements increases. When the gamma is too low, the TV comes out of black too fast. This means that the blacks are black, and the whites are white, but the grays in the middle (especially the darker grays) are brighter than they're supposed to be. This causes shadow details to have a "hazy" look to them. LCD TVs are famous for this. When the gamma is raised to the proper value, the TV doesn't come out of black so fast, and the shadow details remain "shadowy".