One question I get a lot is regarding too
warm and yellow/orange picture after calibration. People are confused by this and I am sure
that they would rather jump back to the good old standard preset they were watching before.
After all, this is how manufacturer had adjusted the picture so it should be good, right?
Well, not really. If you have seen my calibration videos, you
know that I always make a comment about picture quality you get by default. My remarks are
always the same and they end up like this – as soon as you finish the initial TV setup,
go to the picture options menu and select preset called movie or cinema, THX Day or
THX Night, expert or professional and adjust backlight and gamma to be OK for your viewing
environment. Forget about Standard, Normal, Natural and similar presets and don’t even
think about presets such as Football, Stadium, Vivid or Dynamic.
The reason why I want you to do this is because TVs are in terms of picture quality poorly
adjusted. On every TV that I’ve reviewed in the past 7 years, default picture settings
are so inaccurate that they completely defeat the purpose to show you original color, shade
and detail information intended by the content creator. Add to this strong motion interpolation
which affects tempo and clarity of images and recepe for distaster is complete.
One of the reasons why image is so poorly configured by default is because there is
a whole market of calibrators and system integrators ready to take your money for calibration and
picture adjustment. Plain and simple – if you want to watch accurate picture, you have
to pay for it. The thing is, no matter how expensive the
TV is, by default picture will be inaccurate and begging for additional adjustment.
Last year I did a calibration for a friend who bought an 85 inch Sony TV. This expensive
big screen beast should give an awesome picture from the moment it is turned on – right?
Well, big picture yes, but not awesome. Additional adjustments were needed.
Another example – Panasonic’s best ever plasma TV – 60 inch ZT60. Studio Master
panel, fantastic blacks, THX certification. Years and years perfecting plasma technology
in every aspect, THX certified presets and again – picture by default is not accurate
at all. Same goes for LG’s OLED TVs, Samsung’s SUHD
line, Sony’s best Bravias, Philips high end series. Do you see a pattern here?
Default images always have too much blue, which can be clearly seen when measurements
are done. If you take a look at screenshots from SpectraCal’s CalMAN software which I
use to calibrate TVs, you will see several sections called RGB balance, Luminance, CIE
1931 xy, Gamut Luminance and so on… Now let me get a little technical for you
to understand this more easily. I will skip certain items like gamma and sharpness to
keep things simpler. RGB balance diagram shows how red, green and
blue are aligned at different levels from dark to bright. Ideally, they should be at
100% to produce grayscale without any color standing out. But not in reality. By default,
as luminance of the image increases, so do red, green and blue get more apart. As this
happens, grey is no longer grey but rather bluish, reddish or greenish depending on the
TV. Usually it is bluish grey since this gives perception of brighter image.
The CIE 1931 chromaticity diagram was invented in 1931 by the International Commission on
Illumination (CIE). The graph represents all of the colors that are visible to a human
eye. There is an infinite number of color spaces you can fit inside of it, but for HD
content the one that is used is called BT.709 or Rec.709. This triangle of colors has clearly
defined position of whitepoint D65 and primary and secondary colors. Primary colors are red,
green and blue and secondary colors are yellow, magenta and cyan.
This reference points are known to the content creators and are known to the TV manufacturers.
They are the industry standard. OK, so now we know where the targets are,
what does this have to do with RGB balance and the fact that image is yellowish after
calibration? Well, when talking about shades of grey and colors, everything is connected.
If you combine red, green and blue of the same amount, you will get white that will
fall right on the D65 point. If the amount of just one color is smaller or bigger, measured
white will be moved away from D65. This is valid for complete grayscale.
In this example let us start with whitepoint which is precisely on D65 target. I will now
increase red in the TVs white balance menu. See what is happening – white point is moving
towards red. If I increase green, whitepoint will move towards green and same is for blue.
We can also analyse this from the perspective of secondary colors. If we increase red, we
move whitepoint away from cyan, if we increase green whitepoint is moved away from magenta
and if we increase blue whitepoint is moved away from yellow.
So, with this said, let us once again check where is the whitepoint in default picture
preset. You see, it is moved towards blue, which means it has less yellow then it is
should have. To move it closer to D65, we have to reduce blue. We do this by switching
to better picture preset and by doing calibration. So it is completely normal that calibrated
picture looks like it has got too much yellow or orange in it. We basically took extra blue
from the image and aligned red, green and blue to be equally present.
I remember well when I did my first calibration on 32“ Panasonic LCD TV, how picture looked
too warm and with extra yellow. Let me tell you, it was weird at first and I was also
doubting the purpose of calibration. But with little time, education and also by comparing
how picture in movie theaters looks like, I started embracing calibration.
Whether or not you will perform calibration on your TV, my recommendation is that you
spend a minute or two in switching to presets like Cinema, Movie, THX, Expert or Professional
and doing small tweaks on backlight and gamma for optimum result in your viewing environment.
This way you will get closer to what you were suppose to get by default – accurate representation
of movies, TV shows and other content. Hope this video was helpful. I plan to do
more on the calibration subject – if you have ideas about next topic, please tell me
in the comment section. Happy calibrating!