Overdrive and Calibration

Overdrive / Ghosting

The following is a 1/200 sec photo of a moving blade from the AMD FreeSync Windmill demo (this is not a FreeSync panel, but the demo has proven handy for this type of test):

dsc02345.jpg

This was an extremely impressive result. We did note that the OSD adjustment of overdrive had no apparent effect on the output. The above photo was taken with OVD=Off, and we would have expected at least some ghosting in that configuration. We’ve reported the OSD issue to Seiki, but as it is, the currently forced value appears perfectly calibrated and should not need any adjusting anyway. If you click the above image to enlarge it, you will see that there were no TCON related artifacts noted.

Color Calibration

Out of the box, the Seiki Pro display had a passable calibration, with one rather large exception. Default color temperature from the factory was 11,000K! After choosing a more standard 6500K, we got these results in HCFR after only adjusting brightness to 120 cd/m2::

uncalibrated-hcfr-0.png

All values fell just outside the dE=10 threshold, with color shifting towards blue as we got into the darker greys. We then shifted over to dispcalGUI and got these results with further adjustments to the panel OSD RGB levels:

uncalibrated-report.png

Our white point was reasonable since we had dialed back on the greens and reds, but only a full calibration profile would be able to correct our middle grays and darker colors. After a full calibration (details below), this was our result:

calibrated-report.png

As you can see, full calibration does wonders for this panel (and it does make a noticable visible improvement to darker grays and color reproduction). Seiki does not advertise this as a calibrated display, and I would consider its uncalibrated performance as typical, even though the 'Pro' branding may suggest otherwise.

Bit Depth

A quick note on bit depth – many users of 1.07 Billion color capable panels may not realize they need to be in 10 bit color mode to take full advantage of the additional range of the panel:

10-bpc-color.png

This also plays into display calibration, as the application of the profile's color mappings may result in an aliasing effect of color gradients after this math has been applied. Increasing the bit depth effectively reduces this aliasing effect (the same way that increasing resoltion and decreasing pixel size/pitch effectively reduces visible pixel aliasing). Long story short, be sure you are driving your panel at the highest bit depth it is capable of, especially if you care about accurate color reproduction.

Calibration Profile Download

The Windows color profile management interface is a bit of a mess, with the need to select and enable a profile in multiple layers of the interface. The best guide for loading and enabling a profile can be found over at TFTCentral. As of this writing, TFTCental has not yet reviewed the Seiki Pro 40” display, so we used the following tools to generate our own calibration profile:

Our calibration profile was created using the lowest calibration speed in a dimly lit room. Here are the required settings if you wish to use our profile on your own SM40UNP:

  • Brightness: 37
  • Contrast: 50
  • Preset: Select 6500K temperature *before* selecting User Define
  • Red: 96
  • Green: 91
  • Blue: 100
  • Profile download: (HERE)

The above profile was created specifically for a color temperature target of 6500K at a luminance of 120 cd/m2 (nit). Gamma 2.2. Remember that the only way to get a correct calibration on your specific panel is by using a colorimeter on that very panel. The above settings and profile will only get *your* SM40UNP to a perfect calibration if it has the exact same properties as our test sample. A perfect match is unlikely, but this should get you far closer to calibrated than just running with defaults, especially since this panel has an apparent non-linear handling of mid-tones (common in uncalibrated displays).

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