Custom PC - UK (2020-03)

Summary of performance differences by tier

Minimum peak

luminance Range of colour

Typical

dimming

technology

Maximum

black level

luminance

Brightness in

cd/m^2 Color gamut

Brightness in

cd/m^2

DisplayHDR 400 400 8-bit, sRGB Screen-level 0.4

DisplayHDR 500 500 10-bit, 90% DCI-P3^ Zone-level 0.1

DisplayHDR 600 600 10-bit, 90% DCI-P3^ Zone-level 0.1

DisplayHDR 1,000 1,000 10-bit, 90% DCI-P3^ Zone-level 0.05

DisplayHDR 1400 1,400 10-bit, 95% DCI-P3^ Zone-level 0.02

DisplayHDR 400

True Black^400

10-bit, 95%

DCI-P3 Zone-level 0.0005

DisplayHDR 500

True Black^500

10-bit, 95%

DCI-P3 Zone-level 0.0005

The DisplayHDR standards set out several key criteria for classifying different types of HDR display

You can download the DisplayHDR Test app to check
the quality of your display (colorimeter required)

What makes the introduction of HDR quite

such a complex beast is the number of

standards that have been introduced, such as

HDR10, HDR10+ and Dolby Vision. However,

most of these pertain to TVs, cinema and

film standards. When it comes to monitors,

there’s thankfully only one standard that

is worth paying attention to, which is VESA

DisplayHDR. This defines seven classes of

display (five for LCD, two for OLED), each of

which has different HDR characteristics.

There are separate standards for LCD

and OLED because they’re fundamentally

different display technologies with different

pros and cons. While LCDs use a backlight

that’s filtered through an LCD panel, OLED

displays have no backlight but instead

each pixel emits its own light. This means

that LCDs tend to be able to shine brighter

but can’t show as deep a black level (as

some light always leaks through the LCD

panel), so that’s something the LCD HDR

standards lean into. Meanwhile OLED

displays tend not to be able to go as bright

but can show true blacks, due to each

pixel being able to turn off completely.

Starting with the LCD standards, the

first parameter it defines is the maximum

brightness of the display. This is the easiest

to understand, as the number for each

DisplayHDR level tells you the maximum

HDR

Standards

brightness: DisplayHDR 400 is 400cd/m^2 ,

DisplayHDR 1000 is 1000cd/m^2 , and so on.

The next criteria is the maximum

black level; taken in combination with the

maximum brightness level, this gives us

the overall contrast. So, for DisplayHDR

400, the maximum brightness is 400cd/

m^2 while maximum black level is 0.4cd/

m^2 , for a contrast of 1,000:1. Meanwhile

DisplayHDR 1000 drops the black level to

0.05cd/m^2 for a total contrast of 20,000:1.

The next criteria is colour range. The

entry-level DisplayHDR 400 standard

just uses a normal sRGB colour range ( 95

per cent coverage) but requires true 8-bit

colour. Some cheaper displays can only

produce 6-bit colour and use dithering

or other techniques to emulate greater

colour depth, so these wouldn’t qualify for

DisplayHDR 400. Confusing things slightly

is that many DisplayHDR 400 displays

do provide extended colour ranges but

either they don’t extend far enough or

don’t have the other requirements to

qualify for higher DisplayHDR ratings.

Indeed, such displays account for the vast

majority of so-called HDR displays.

Meanwhile, all the other standards

require at least 10-bit colour processing,

although this can be via 8-bit with dithering,

and a wider colour space coverage of

90 per cent of DCI-P3. The top of the

line DisplayHDR 1400 standard requires

95 per cent coverage of DCI-P3.

When it comes to the OLED standards,

these shift the emphasis from peak

brightness to peak darkness. So, while

DisplayHDR 400 True Black tops out

at just 400cd/m^2 , its black level is

rated as 0.0005cd/m^2 , for an effective

contrast of 800,000:1 (in reality it can

be infinite) while DisplayHDR 500 True

Black bumps this to 1,000,000:1. Both

standards also require 10-bit colour.

FEATURE/ ANALYSIS