Reviewed: THX level I & level II calibration training

THX may be headquartered in San Rafael, California, but Inside CI only had to take a short trip from our North West London base to attend the company's legendary calibration training, which is held annually at JVC's offices in the capital.

The THX package, comprising Level I and Level II training, is split over three days; day one is for beginners and provides a general introduction to the THX philosophy. It's followed by an advanced course, which comprises intensive hands-on followed by an exam which when passed bestows THX Certified Professional Calibrator status. Our presenter for the duration was Gregg Loewen, a THX veteran from Lion Audio Video consultants.

The THX standard was developed in 1983 by George Lucas and Tomlinson Holman, as a division of Lucasfilm, with the overriding goal of offering the best possible movie experience. The standard has evolved considerably since them, and THX is now a company in its own right, but the original tenets of THX still hold true.

Hands-on approach
The course itself is designed for professional video calibrators, installers and integrators, and when we attended had attracted a mixed bag of installers from around the world. The programme is very hands-on and delegates are presented with a list of exercises and goals. The initial approach is practical: what model number is the display? How do you access the contrast, brightness, colour, tint and sharpness controls? What's the difference between white and black level? The idea is to quickly build knowledge and there's plenty of interaction with other installers. 

Loewen breezes through his slides, describing colour space and colour gamut, and introducing the all important Rec.709 RGB triangle. The top five elements to a great image, he says, are optimal black level, contrast ratio, accurate colours and grey scale, image resolution and most important the quality of the source material. Getting to grips with calibration means you need to get to know the basics.  Things have come a long way since 1939, when televisions just processed a luminance signal…

THX Level I training
Day one is both gentle and fascinating. The first step when calibrating a display involves setting up the black level or brightness, we're told. We're presented with a THX test disc that has a pattern with a THX logo. On 8 bit processing the correct black level should be 16 on the scale, the THX logo had a shadow set at about 12; if the panel is set wrong you will see the shadow. Adjusting the brightness causes said shadow to disappear. Going to a still image demo, the detail in the blacks was dramatically different after adjustment. All very straightforward.

Next up on the THX video calibration agenda is white level. This follows the same procedure as black level, this time adjusting the contrast slider. After getting the white balance right delegates are prompted to manage the light output level. The correct setting for flatpanels is 35 foot-lamberts, explains Loewen, and for front projection it's 16 foot-lamberts.

The exercises are set out in labs, which proves a very clever way to absorb information. Terminology is the key thing here, memorise what values you are looking for and you're half way there. We found the course hand-out to be a great tool, jot down what you are looking for and hey presto you get what you are doing. Gregg Loewen delivers information in a unique way that really worked for me, he stresses a point and asks you many questions; by lunchtime my brain had memorised every value...

THX Level II training
While the Level I course covers basic calibration you'll need to attend the two-day Level II training session to get your screens to Reference Level. Colour controls can be adjusted by either putting on filtering blue glasses that are provide with the Blu-ray test disc or, if the panel has it, by switching off the red and green elements. It's worth pointing out that the filter approach is not perfect, so if you can turn off the colours in-screen this offers a better calibration option. Either using the filter glass or panel adjustment option, you are looking to get the blue bars to blend together with the white.

When the course moves onto equipment and software, it all starts to get far more involved.  Mastering this is the only way you can get THX certification. The on-site process itself is largely automated, calibrators simply start at top of page and work their way through all the tests. When complete you can run your report showing settings before you started and the calibrated results afterwards, this can then be given to the customer with your invoice.

THX course verdict
In our view, both THX Levels are well worth the investment for AV installers. Once you get out in the field and start calibrating screens, you'll be able to get your money back really soon. As the day goes on, the course digs deeper. Days two and three are not for the faint hearted, but having experienced how to calibrate screens the THX way, you'll feel like the best trained installer in the country. You can expect to charge good money for a calibration service when fully certified. Be aware though that it is going to take a large initial investment in equipment. You need to budget around £1,600 for software and over £1,000 for an image analyser. Also, don't think your THX status lasts forever; you'll have to be reviewed every two years to keep hold of the prestigious status of THX Certified.

Also read:
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