Brightness and Contrast

Going straight into the brightness and contrast metrics, we know HDR's calling card is to permit those bright whites and dark blacks. For DisplayHDR 1000, and UHD Premium, 1000 nits (the common non-SI term for cd/m2) is the requirement. So for brightness of white levels, it's no surprise that in HDR mode the PG27UQ reaches that coveted mark.

Outside of HDR, brightness is also useful in gauging visibility/usability in conditions of bright and direct ambient light, i.e. outdoors. For moderately lit indoor use, the typical 200 to 300 nit range of desktop monitors is more than sufficient. In terms of factory defaults, the PG27UQ is set at 80 for brightness, which is around 266 nits. 1000 nits is much too bright for day-to-day usage, as is 500 nits.

White Level -  i1DisplayPro
*In HDR mode, there is an adjustable 'reference white' setting, defaulted at 80 nits, instead of a brightness setting. At that default setting, the PG27UQ displayed the HDR test pattern at 1032 nits.

Because HDR has a static 'reference white' level instead of brightness, there isn't really an equivalent to minimum brightness white level as it isn't utilized in the same way; for the PG27UQ, reference white can be set between 20 to 300 nits.

Otherwise, enabling the Windows 10 'HDR and Wide Color Gamut' mode puts the monitor into its HDR mode; additionally, that Windows 10 setting provides a brightness slider governing SDR content while in HDR mode. So at 100% SDR brightness, the display pushes past 500 nits. For users, it works nicely to avoid SDR dimness when HDR is enabled, and also providing the option to boost up to much higher brightness if desired.

Black Level - i1DisplayPro
*Represents black levels corresponding to the default 'reference white' setting of 80 nits.

IPS-type panels are often known for their 'backlight bleed' and so relatively higher black levels. Without its local dimming capability, the PG27UQ isn't much of an exception. Enabling variable backlighting (FALD) in the OSD brings the black levels to HDR tier performance, and can be enabled on SDR mode at the cost of maximum brightness white levels.

Contrast Ratio -  i1DisplayPro
*Contrast ratios calculated from default reference white of 80 nits

The good range between bright whites and dark blacks translate into high contrast ratios for the PG27UQ. While we don't have any other HDR monitors for comparison, the contrast ratios are really in their own class, especially as only HDR content will take advantage of the brightness and be (properly) displayed. Otherwise, in pure SDR mode, the PG27UQ resembles a solid IPS-type SDR monitor. Just enabling the direct LED backlighting in SDR mode improves contrasts considerably on the strength of its black levels.

Design and Features SDR Color Modes: sRGB and Wide Gamut
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  • Flunk - Tuesday, October 2, 2018 - link

    I'd really like one of these, but I can't really justify $2000 because I know that in 6-months to a year competition will arrive that severely undercuts this price.
  • imaheadcase - Tuesday, October 2, 2018 - link

    That's just technology in general. But keep a eye out, around that time this monitor is coming out with a revision that will remove the "gaming" features" but still maintain refresh rate and size.
  • edzieba - Tuesday, October 2, 2018 - link

    The big omission to watch out for is the FALD backlight. Without that, HDR cannot be achieved outside of an OLED panel (and even then OLED cannot yet meet the peak luminance levels). You;re going to see a lot of monitors that are effectively SDR panels with the brightness turned up, and sold as 'HDR'. If you're old enough to remember when HDTV was rolling uout, remember the wave of budget 'HD' TVs that used SD panels but accepted and downsampled HD inputs? Same situation here.
  • Hixbot - Tuesday, October 2, 2018 - link

    Pretty sure edgelit displays can hit the higher gamut by using a quantom dot filter.
  • DanNeely - Tuesday, October 2, 2018 - link

    quantum dots increase the color gamut, HDR is about increasing the luminescence range on screen at any time. Edge lit displays only have a handful of dimming zones at most (no way to get more when your control consists of only 1 configurable value per row/column). You need back lighting where each small chunk of the screen can be controlled independently to get anything approaching a decent result. Per pixel is best, but only doable with OLED or jumbotron size displays. (MicroLED - we can barely make normal LEDs small enough for this scale.) OTOH if costs can be brought down microLED does have the potential to power a FALD backlight with an order of magnitude or more more dimming zones than current models LCD can do; enough to largely make halo effects around bright objects a negligible issue.
  • Lolimaster - Tuesday, October 2, 2018 - link

    There is also miniled that will replace regular led for the backlight.

    Microled = OLED competition
    Miniled up to 50,000zones (cheap "premium phones" will come with 48zones).
  • crimsonson - Tuesday, October 2, 2018 - link

    I think you are exaggerating a bit. HDR is just a transform function. There are several standards that say what the peak luminance should be to considered HDR10 or Dolby Vision etc. But that itself is misleading.

    Define " (and even then OLED cannot yet meet the peak luminance levels)"
    Because OLED can def reach 600+ nits, which is one of the standards for HDR being proposed.
  • edzieba - Tuesday, October 2, 2018 - link

    "HDR is just a transform function"

    Just A transform function? [Laughs in Hybrid Log Gamma],

    Joking aside, HDR is also a set of minimum requirements. Claiming panels that do not even come close to meeting those requirements are also HDR is akin to claiming that 720x468 is HD, because "it's just a resolution". The requirements range far beyond just peak luminance levels, which is why merely slapping a big-ass backlight to a panel and claiming it is 'HDR' is nonsense.
  • crimsonson - Wednesday, October 3, 2018 - link

    "
    Just A transform function? [Laughs in Hybrid Log Gamma],"

    And HLG is again just a standard of how to handle HDR and SDR. It is not required or needed to display HDR images.

    "HDR is also a set of minimum requirements"

    No, there are STANDARDS that attempts to address HDR features across products and in video production. But in itself does not mean violating those standards equate to a non-HDR image. Dolby Vision, for example, supports dynamic metadata. HDR10 does not. Does that make HDR10 NOT HDR?
    Eventually, the market and the industry to congregate behind 1 or 2 SET of standards (since it is not only about 1 number or feature). But we are not there yet. Far from it.

    Since you like referencing these standards, you do know that Vesa has HDR standards as low as 400 and 600 nits right?

    And I think you are conflating wide gamut vs Dynamic Range. FALD is not needed to achieve wide gamut.

    And using HD to illustrate your points exemplifies you don't understand how standards work in broadcast and manufacturing.
  • edzieba - Thursday, October 4, 2018 - link

    "And HLG is again just a standard of how to handle HDR and SDR. It is not required or needed to display HDR images."

    The joke was that there are already at least 3 standards of HDR transfer functions, and some (e.g. Dolby Vision) allow for on the fly modification of the transfer function.

    "And I think you are conflating wide gamut vs Dynamic Range. FALD is not needed to achieve wide gamut."

    Nobody mentioned gamut. High Dynamic Range requires, as the name implies, a high dynamic range. LCD panels cannot achieve that high dynamic range on their own, they need a segmented backlight modulator to do so.
    As much as marketers would want you to believe otherwise, a straight LCD panel with an edge-lit backlight is not going to provide HDR.

    "And using HD to illustrate your points exemplifies you don't understand how standards work in broadcast and manufacturing."

    Remember how "HD ready" was brought in to address exactly the same problem of devices marketing capabilities they did not have? And how it brought complaints about allowing 720p devices to also advertise themselves as "HD Ready"? Is this not analogous to the current situation where HDR is being erroneously applied to panels that cannot achieve it, and how VESA's DisplayHDR has complaints that anything below Display HDR1000 is basically worthless?

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