Updated March 30, 2015: added setup details; corrected 2-point white balance chart
I recently spent an afternoon calibrating the picture of a 70-inch Vizio P-Series 4K UHD television, and I wanted to share my findings.
I recorded the TV's color and grayscale performance prior to making any changes. In this case, the owner had done little besides enable the TV's Calibrated Dark picture preset that reduces the backlight level and targets a 2.2 gamma (electro-optical transfer function) setup.
Not bad! Vizio is clearly performing a factory calibration on its P-Series televisions before they leave the assembly line. RGB mixing with this factory preset was consistent although slightly too blue, and the measured gamma response (white line) tracked well with the preset's claimed 2.2 value.
Default color quality
A check of the Dark Calibrated preset's default color quality across saturation levels revealed an average overall performance.
Most of the above results exhibited an error value above 3 (green line) indicating that a person with normal vision would see a difference between this TV's output and the target HD reference color in motion video; with static side-by-side color comparisons the ideal maximum error approaches 1.
Compare the above to the result obtained after adjusting the TV's 2-point white balance controls.
Nice! A flatter response overall (grayscale and gamma), although some of the darker grays are now slightly green positive; a blue positive error is preferable to red or, especially, green positive errors.
These are the values I applied in the Color Calibration > Color Tuner menu to obtain the above result (starting with the Calibrated Dark preset).
Please keep in mind that every TV, including every P-Series, is slightly different; the values I applied may not produce similar results with another, albeit similar, television.
Take it to 11
The Vizio P-Series has an 11-point white balance setup that can be used to fine-tune the product of its 2-point controls. Using these controls, this was the result I settled upon.
The average white balance error was slightly reduced and I was able to improve upon the balance (RGB) of the darker grays. Also, gamma tracked slightly closer to the 2.2 spec.
The 11-point white balance setup for this TV used the following values:
The P-Series 11-point white balance controls would benefit from increased granularity, but I was pleased with the final results.
If I had to pinpoint a shortcoming of the P-Series' picture quality, it would be primary color (red, green, blue) accuracy; fully-saturated red and blue were particularly challenged. Compare the above color saturation errors with this result after performing a 11-point white balance setup.
Much improved but red results were mixed as the lightly saturated levels exhibited increased errors. Diving into the P-Series' Color Tuner tool, this was the final color saturation error result.
I was pleased with this color error reduction. Primary color errors at 100% saturation were a bit higher than I like to see, but this was a hardware limitation involving the interaction of the P-Series' LED light source and its color filter. Here is above data plotted on a CIE chart.
Notice how far off 100% red and blue are compared to the target values (white boxes). However, this is a solid improvement compared to where we started (see below). Here are the color tuner settings I applied to achieve the above result.
Below is the color saturation plot prior to calibration; fine-tuning the P-Series primary and secondary color responses for improved accuracy resulted in a more natural-looking and pleasing picture.
Another test that I find useful is a color checker tool that measures a couple of dozen hues that include simulated skin tones, foliage, and a few shades of gray.
Much better! A few hues pushed past the 3.0 error level; the orange/yellow errors were due to the rather extreme error of the TV's red primary.
Finishing off the P-Series setup, here is the configuration I used for the controls in the "More Picture" settings menu.
The Active LED Zones control is for toggling the full-array local dimming system on/off. Smooth Motion Effect ruins the look of movies so it was disabled. Clear Action enables the TV's backlight blinking feature for improved motion resolution without unsightly video smoothing artifacts. I usually disable all forms of video noise reduction when calibrating most TVs, however, this time I selected Low to help minimize compression artifacts and other visual quirks that were noticeable when the TV was processing and displaying non-4K video sources.
Software updates have made the Vizio P-Series a better television since its Summer 2014 release. The improvements that video calibration enabled in this TV's color accuracy and grayscale consistency were evident in its reproduction of movies and television programming; the sense that we were now seeing a picture that more faithfully represented the careful work of the director, cinematographer, and editors was obvious and pleasing to all. Not a bad result for a value 4K UHD TV.