[One (M8) General] puremind:
HTC did it again but worse. Last year displays were different in color temperature but maintained similar contrast. This year the difference in display calibration is worse.

Before receiving my own unit, I tested 2 devices in the shops. The first one had worse contrast and too low gamma (less punchy brightness transition from dark to light tones). I was disappointed with the display (let's call it Type A).

Later on, I went to another shop and the display looked gorgeous. Higher contrast, accurate gamma and more neutral greyscales (let's call it type B).

Today I received my unit and unfortunately, the display was Type A display. Here are the results of the "poorer display". Unlike last year, it is not possible to determine the actual display ID by looking this up in the last_ksmg file in the proc folder under the root. The access is denied. So unless we root a device, we cannot determine the display ID.

As can be seen below, the color temperature and greyscale accuracy is mediocre. Contrast is only average. Chromaticity overall is good but red is oversaturated.

Brightness: 503cd/m²

True Contrast: 1,000:1

Dynamic Contrast: 1378:1

White Color Temperature: 7395°K

Average Color Temperature: 7417°K

Note that on this display, the i1 Dislay pro used by many press reviewers will overestimate color temperature by 5.5% on this particular display. So if you see values around 7900°K, this is broadly equivalent to the 7,400°K that I (and Anandtech) measured. UK Harware review probably also had a Type A display however the contrat values are likely due to methodology.

Although I haven't tested extensively, I can already tell that the dynamic brightness adjustment is still taking place, though it works differently v. last year's implementation. This is why the contrast values observed in the press reviews very widely between 980:1 and over 2300:1!

I will be measuring Type B displays in the shops to nail down the differences based on the same methodology (100% Voodoo Test patterns).

Greyscale

Color Space

Currently available reviews for the HTC One Display pending

Tests in English

25.03.2013 BGR GSMArena: 567cd/m² Brightness | 1,256:1 Contrast

26.03.2013 USA Anandtech: 497cd/m² Brightness | 1,300:1 Contrast | 7,341 Color Temperature (Delta E = 5.2)| Chromaticity: excelllent (Delta E = 3.87)

20.03.2013 GBR pcpro: Brightness not mentioned | 1,687:1 Contrast (measured with i1 Display Pro)

14.03.2013 GBR uk.hardware.info: 508cd/m² Brightness | Black Level: 0.2cd/m² | 2,541:1 Contrast | 7,856K Color Temperature (measured with i1 Display Pro)

25.03.2013 USA laptopmag: 447cd/m² Brightness | Chromaticity: Good (Delta E = 6.1)

German

20.03.2013 DEU Computerbase.de: Not yet published DTP94)

04.04.2013 DEU PC Welt 454cd/m² brightness | 2,555:1 contrast

31.03.2013 DEU Chip.de: 482cd/m² brightness | 1420:1 contrast

02.04.2013 DEU notebookcheck.com: Not yet published

Dutch

02.04.2013 NLD Tweakers.net: 505cd/m² | 1,624:1 contrast | 7,005 color temperature (Delta E = 7.7)| Excellent Chromaticity (Delta E = 4,78) (measured with i1 Display Pro)

Russian

26.02.2013 RUS 3dnews.ru: Not yet published (measured with Spyder 4)

03.04.2013 RUS high-tech@mail.ru 486cd/m² brightness | 988:1 contrast (1300:1 dynamic) | 8,000K white temperature

French

03.04.2013 FRA Les Numériques 480cd/m² | Contrast 1279:1 | Chromaticity: good (Delta E = 4,5) (measured with i1 Pro or i1 Pro 2 tbc.)

02.02.2013 FRA 01.net 527cd/m² brightness | 2,509:1 contrast (measured with Konica Minolta CA-210)

For reference, here are the luminance ranges of the color testing devices listed above.

i1 pro__________________________ 0.20 cd/m² to 300 cd/m²

i1 pro 2_________________________0.20 cd/m² to 1200 cd/m²

Chroma 5/Sencore Color Pro V_______0.01 cd/m² 1000 cd/m²

Spider 3/4_______________________0.02 cd/m² 5000 cd/m²

i1 Display 2______________._____._.__0.02 cd/m² 3000 cd/m²

i1 Display 3/i1 Display Pro/C6___._____0.003 cd/m² 1200 cd/m²

Konica Minolta CA-210______________0.01cd/m² 1000 cd/m²