OLED TVs are available on the market for some time now, there are many reviews out there
but I honestly cannot say that I've seen any long term testing done with this new exciting
technology.
I wanted to change that so in December 2014 I received LG's 55“ EA980V OLED TV for long
term, marathon testing.
Reason: OLED TVs are great if you test them for a week or two, but what will happen after
longer periods and with normal usage?
People are talking about blue component of the OLED material that cannot keep up its
luminance and should make picture look reddish or greenish over time.
Also, what about image retention or burn in – we know that it exists.
In order to see what is going on, I placed LG's OLED TV in my living room and used it
as any other TV that I've owned.
I was watching all kinds of content, standard and high definition, internet video, Blu-rays,
played a little bit of games and used built-in apps like YouTube.
To avoid relying only on my eyes, I did a complete ISF calibration on 18th of January
this year and used calibrated Expert 1 preset since.
OLED Light, which is basically same as Backlight on LED LCD TVs was most of the time at half
of its maximum value, but sometimes I've increased it to 70%.
Calibration was made for Rec.709 colorspace.
After around 750 working hours, on 2nd of October this year I've rechecked using SpectraCal's
CalMAN software how Expert 1 preset looks and here are the results:
As you can see from the graphs, there were no big changes in picture characteristics.
On White Balance chart we can see that blue stimulus is reduced, but overall DeltaE 2000
errors are below value of 3.
DeltaE is a rough estimate of sum of errors in colors, with value below 3 considered not
visible to the average human eye.
Color gamut is the range of colors that a particular device can show.
In this case we see no significant change compared to the calibrated state, meaning
that colors that are mastered on Blu-ray discs will be precisely displayed on the TV screen.
If we check DeltaE errors for colors, we see them below threshold of 3, with the biggest
errors in blue.
Same situation was measured in January, so again, no big differences in this regard as
well.
I also checked color gamut coverage since now I use CalMan 5 Ultimate for business version
of the calibration software.
LG's OLED TV can display 99% of Rec. 709 and 89% of DCI-P3 which is a standard used in
digital theaters and which should come to our living rooms with the advent of UHD Blu-ray.
Peak brightness when 18% of the screen is covered in white was 152.6 nits in January
and 146 nits in October.
This is a 5% decrease which cannot be seen with bare eyes.
Just for comparison, I've tested one 39“ Panasonic LED LCD TV 2 years ago and after
9 months its brightness fell around 15%.
In short, OLED does not show any concerning behaviour in this regard.
Black is still pure 0.00 nits and black level is set so that value of 16 is reference black.
I still haven't properly tested Panasonic's first OLED TV, but I would say that performance
is very similar, at least when compared to the OLED TV I am using.
Although I was using apps, listening to music with built-in media player, none of the static
parts of the interface left any traces on the screen.
Yet, I've received feedback from different stores and also saw with my own eyes burned
in LG's logos and lower thirds of the news channels, so image retention and burn in are
possible.
Still, for typical usage without constantly using OLED TV as a PC monitor there should
be no worries.
So what is the conclusion of this analysis?
After 10 months, LG's OLED TV did show small changes in picture characteristics, but they
are still below treshold that would be visible to the human eye.
Previously conducted marathon tests like this one did show even bigger differences, so for
the time being, OLED technology seems to be on the safe side.
Testing continues and I will report again in January 2016, precisely 1 year after the
initial calibration.
Stay tuned...