Tonight I measured a Galaxy S6 unit in all its screen modes:

– Adaptive display
– AMOLED cinema
– AMOLED photo
– Basic

To anticipate some marketing or analysts claims, here are graphs and data representing the display of one unit, at 100% brightness.

Note: Those are based on preliminary results from a colorimeter only and I will apply some corrections based on the readings of a spectrophotometer.

If you look only at the 2D CIE 1932 gamut and saturations graph, the gamut and saturations seems to match rather closely to the sRGB or Rec.709 standards. It will affect the CIE diagram slightly but not the curves.

However it would be a mistake to claim that this display is color accurate to any existing standard, the reason being that the grayscale luminance and gamma response are wrong.
In fact, the average gamma ends up at 2.49 here which is really high: it makes things darker and more contrasty than they should (an approximate average gamma is 2.2)

So while the screen might look satisfyingly accurate if you look only at one particular graph, the Galaxy S6 display in Basic mode can't be trusted for color-critical work like video or photo editing.

Also, because of the correction required to reduce the saturation that's mechanically increased by a higher gamma, the overall appearance in Basic mode is inconsistent, and looking "off" to a trained eye.

There's more to say about the other modes but that'll be for later 🙂
The real #MWC15 starts in less than 8 hours!

Don't hesitate to point authors of a claim like "very accurate display", "most accurate ever" to the graphs attached.
They're making a mistake in their analysis: you can't look at only a fraction of the data, represented in a specific way and claim that it validates all the rest. But apparently it's a very common mistake.

#supercurioBlog #display #measurements #color #critic #Samsung


In Album About Samsung Galaxy S6 Basic screen mode

Source post on Google+

But that's not all – this is actually the first phone with an AMOLED screen that is as faithful in rendering hues properly – color and grayscale errors are minimal

The only downside to the Note 4's panel is its gamma value of 1.97, which is below the reference value of 2.2 – the iPhone 6 Plus is close to perfect, at 2.18. In practice, this means that the Note 4 delivers a punchier, more contrasty image than it should, though the effect is not so overdone as to be annoying or distracting.

Average gamma: 1.97
Incompatible with:
– grayscale errors are minimal.
– this means that the Note 4 delivers a punchier, more contrasty image than it should

Conclusion: +PhoneArena authors need some more training on display analysis.

Assuming the average gamma is indeed 1.97 and it is not measurement error and/or inadequate measurement methodology.
A gamma that's too low means the response curve is too high, too bright.
A gamma of 1.97 will give a fairly washed out appearance and the appearance of lack of visual contrast and punch to the images.

Gamma at 1.97 is a pretty large deviation: grayscale error can't be minimal.
It also has the exact opposite effect than what +PhoneArena describes: "punchier, more contrasty image than it should"

It's nice to have some data, but some appear to be invalid and conclusions are contradicting the data.
Not quite there yet +PhoneArena

#supercurioBlog #display #color #measurements #critic

Samsung Galaxy Note 4 vs Apple iPhone 6 Plus
Nowhere else does the rivalry between Apple and Samsung cut as close to the bone as with the iPhone 6 Plus and Galaxy Note 4. Encroaching onto true Samsung territory, it’ll be on the 6 Plus to prove itself better than the Note 4, and that will be no small feat given the years of experience that sprung the latter on the scene.

Source post on Google+

So now, having manually selectable screen rendering presets is considered as color management

You'll find also the usual:
– 2.35 gamma instead of 2.2 but "very good accuracy"
– only 21 color measured at only 100% and 50% saturation to be sure not showing too much of the color deviations

I couldn't read the whole thing, my BS detector was tripped up to angry levels this time.. color management! oh come on. I have no words.

This whole series of "shoot-out" is either result of manifest incompetence or purposefully misleading (or both)

#supercurioBlog #color #measurements #critic #display

Galaxy Note 4 and Note Edge OLED Display Technology Shoot-Out
Introduction. A key element for a great Smartphone has always been a truly innovative and top performing display, and the best leading edge Smartphones have always flaunted their beautiful high tech displays. The Galaxy Note and Galaxy S series are flagship Smartphones for Samsung to show off …

Source post on Google+

Here's an LG G3, Korean LG-F400K display measurements ran today with my spectrophotometer and my in-house program

Issues encountered:

Luminance curves: shadows are too bright, upper mids and highlights are too dark.

Too much blue and green (or not enough red), getting bluer in shadows and extreme highlights

Contrast ratio measured at 718:1 on this unit.
Max brightness gets to 332cd/m², however outdoor readability seems still okay.
When the device get warm, it reduces maximum brightness.

As usual, the manufacturer tries to compensate for a misplaced white point by boosting color saturation, introducing even more color rendering inaccuracies.
The saturation boost also tries to compensate the washed out appearance due to inadequate gamma curves but the results is not subjectively not looking nice.

Examples of boosted saturation introducing visible clipping and loss of details:
75% saturated magenta gets +21.5% = 96.5% saturation.
81% saturated green gets +16% = 97% saturation.

The way saturation boost is implemented also decreases colors luminance, increasing the strange looking aspect of saturated colors (most visible on cyan and blue)

What's missing from those measurements:
– Intense sharpening effect applied on every content and can't be disabled
– Slight dynamic contrast, introducing a little bit of banding, serving no real purpose and that can't be disabled.

I would rate it as one of the poorest flagship displays I've seen for a while overall. The sharpening present is off-putting and colors not appealing.
LG seem to have bet everything on "sharpness", focusing on high resolution & pixel density, and then over-killing it with sharpening artifacts.

#supercurioBlog #color #measurements #display #LG


In Album LG G3 display measurements F400K

Source post on Google+

While testing some changes in the color science math of my calibration and measurement program, I took a look at my Galaxy S4 I9500 set to Movie Mode, at 100% brightness

This is is the mode described as color-accurate here:

The Galaxy S4 Movie Mode provides very nice, pleasing, and accurate colors and picture quality
Movie Mode, Very Good Calibration
Very Good Images, Photos and Videos have very good color and accurate contrast

Based on those high precision measurements, I beg to differ. My rating would be poor or very poor.
Color manipulations are so wrongly done that some secondaries (cyan and yellow) are not even in line with primaries!
Well, this is an example of what happens when using not enough data to cherry-pick evidence that suit your established conclusion.

That's the reason why I'm committed to provide display analysis software and training to any reviewer interested.
The current source , considered as reference is not as good as it should, also possibly biased based on the fact its conclusions doesn't even match the data published.

Anyway. Yay, the new code works great 🙂

#supercurioBlog #display #color #measurements #critic


In Album Galaxy S4 Movie Mode

Source post on Google+

Today, #MWC14 last log:

In terms of smartphone displays I measured:
– Gionee's Elife S5.5
Quite incredible super thin device from a manufacturer you might have never heard of, but who realized something that forces respect.
At 5.5mm, it provides the same battery capacity as the 8.59mm Nexus 5.
S5.5 display is a Super AMOLED 1080p that looked similar if not identical to the Galaxy S4 one.
Camera sensors and app are quite convincing (5Mp front) with plenty of cool & advanced features that are actually usable.
I also grabbed a Voodoo Report from it as I'm curious about it's Octacore Mediatek SoC.

– A Firefox OS Huawei smartphone, the Y300.
In the middle of other new Firefox OS devices, I picked this one as its display is IPS and for the price I must say it doesn't look bad at all. Incredibly better than its siblings using TN displays for sure.

– Nokia Lumia 1520
I'm sure you know about this one already.
Lumia's display is quite impressive in person so I had to take readings about this.
For the record, I had to modify my measurement HTML5 app because IE browser was caching AJAX requests more than anticipated ^^.
Cache-control headers did the trick.

– Nokia Lumia Icon
Probably the most interesting and usable Lumia smartphone at the moment. It's the same hardware platform as the 1520: S800 / 1080p display but using a 5" Super AMOLED instead of 6" IPS.

– Xiaomi Mi3
Qualcomm's booth had a pretty amazing collection of Snapdragon-equipped device.
Because, you know.. they're very much in most smartphones those days 😀
I had little time left in the end but still measured this one as it's not so easy to get a hold of it, and also the display and it's factory calibration were pretty convincing and I look forward processing the measurements to confirm some very quick first impressions.

Today was also the opportunity to spend more time with +Richard Lai, who demonstrated extraordinary group hug capabilities then accompanied me to +Ubuntu booth.

Good folks at Canonical appreciated this original usage of Ubuntu touch.
− the Nexus 7 in these pics, driving a colorimeter and a spectrophotometer using my app runs under the ARM & touch oriented port of this Linux distribution.
I tried to made a demo for them and despite an alpha development stage, if everything worked perfectly during the show it didn't for a demo to them.
Oh well, typical 😀

Today was also the opportunity to talk with +Qualcomm engineers. I spent hours in total the last 3 days talking with a senior product manager and a software engineer specialized in hardware video processing and scaling algorithm.
Both were as knowledgeable as it gets and knew everything about display calibration as well, which was refreshing as not common.

Qualcomm will take a closer look at my Nexus 7 display calibration development drivers & algorithm, they were surprised I was able to do what I'm working on already without their help, and recognized it's a valuable usage of their silicon 😉

At the end of the day I had the privilege to meet, talk and shake hands with +Mark Shuttleworth who actually knows a lot as well about display calibration and why mobile OS should be capable in this area as well.
His mention of color accuracy on Ubuntu Edge introduction video was no accident.

In the next days I'll process the spectral and reference color data from the spectro sensor to get correct the colorimeter readings from all those displays and share that with you.

Already I must say see a positive trend since last year.
Higher resolution displays yes but also more capable of reproducing the full color gamut − sometimes too much.
Most manufacturers seem to buy factory calibrated panels but some still downgrade them with uninspired processing.
Overall it's pretty positive and this was an awesome, far too short MWC

#supercurioBlog #display #measurements #MWC


In Album 2014-02-27

Source post on Google+

Measuring +Sony Xperia Tablet Z2 in a private media booth

I made sure taking a good sample device – that's still a prototype as some had completely yellow displays 😉
The one I have here should be most representative of the final product hopefully.

I'm curious about this tablet because the gamut seem wide as well, however there's something going on with the saturation I don't like too much.
Well, measurements will tell 🙂

Also I get to measure 2 more Z2.

#supercurioBlog #display #measurements #MWC


Source post on Google+

Early measurements results of a +Sony Xperia Z2, captured from +Erica Griffin computer screen as she couldn't wait to see the results

I'm impressed by the capabilities of this device so far.
Gamut is large, comparable to Super AMOLED displays.
On the Z2 devices demonstrated in Barcelona, there's no chroma saturation boost added. If color seem plenty intense they don't look too over-saturated like we've seen often on Samsung wide gamut panels.

A bit later I'll publish the full measurements corrected based on a reference spectrophotometer, for precise color temperature and gamut evaluations.
Also, planned : wavelength spectrum to look even more in depth into this new +Sony backlight technology!

#supercurioBlog #display #measurements #MWC


In Album 2/24/14

Source post on Google+