How should a grading monitor and room be set up?

The SDR reference: BT.2035 with BT.1886

ITU-R BT.2035 exists so that a programme judged in one facility looks the same in another. For the display it sets reference white at 100 cd/m² with D65 chromaticity, reference black below 0.01 cd/m², and the tone response of BT.1886. For the room it sets illumination of 10 lux, a background behind the monitor at about ten per cent of reference white and of the same D65 chromaticity, dark matt surfaces elsewhere to keep stray light off the screen, and a viewing distance of 3.2 picture heights for HD. It adds that displays intended for consumers should not be used for professional evaluation.

Why the surround changes the picture

The eye adapts to everything in view, not to the screen alone. A bright surround raises the adaptation level and makes the picture's shadows look blacker and its contrast higher; a dark one does the opposite, and a colourist compensates without noticing. A coloured wall or a warm lamp shifts the adapted white, so a neutral grey on screen appears tinted the other way and gets corrected for a cast it does not have. This is why the standards fix the luminance and the chromaticity of what lies behind the monitor and not just the monitor.

The HDR reference

ITU-R BT.2100 specifies its own environment for HDR. The surround is neutral grey at D65 and 5 cd/m², the periphery no brighter, and light should not fall on the screen. The display should reach at least 1,000 cd/m² with black at or below 0.005 cd/m². The surround is darker than the SDR one in absolute terms and far darker relative to the display's peak. HDR reference white is a separate matter from peak: ITU-R Report BT.2408 puts it at 203 cd/m², so most of the display's range above that is headroom for highlights.

Grades of monitor

The EBU's Tech 3320 sorts professional monitors into grades. A Grade 1 monitor is defined as a measuring instrument for the visual evaluation of image quality, and its listed uses are camera control, colour grading and quality control. Grade 2 monitors have wider tolerances and serve previewing, edit suites and control rooms. Grade 3 monitors are observation devices. For SDR the document requires a Grade 1 monitor to reach black below 0.05 cd/m², with looser limits for the other grades. It treats HDR monitors in a second part with their own definitions.

Two screens that measure alike can look different

BT.2035 cautions that commercially available instruments may give different results because of the technologies they use to sense light, and that a measurement made with the standard 1931 observer functions can mislead between display types. Dolby's guide makes the practical point: displays of different technologies may exhibit metameric differences, so the HDR and SDR monitors in one suite should be of the same technology. An OLED reference monitor and an LCD television matched by a meter to the same white may not look matched to a person.

Nothing on this site is a calibrated reference. A web page is shown by a browser that may or may not colour-manage, on a screen of unknown white point, brightness and response, so no still or swatch here can reproduce a graded image.

The data

How to check it yourself

1. Measure white on the monitor with a probe suited to its technology: luminance and chromaticity against the target, after warm-up.
2. Set black with a PLUGE pattern in the room lighting you will work in, not in darkness.
3. Measure the wall behind the screen. It should be neutral and, for SDR, near a tenth of the monitor's white.
4. Sit at the working distance and look for reflections of lamps, windows and bright clothing in the screen.
5. Repeat the measurements on a schedule; displays drift, and a room changes when someone moves a lamp.

What the evidence says

Each statement is labelled by kind — established fact, a standard’s requirement, observed market data, a convention, or Colourwise’s own interpretation or analysis — with the strength of the evidence behind it.

• StandardStrong evidence

  ITU-R BT.2035 (07/2013) recommends, for evaluating HD programmes, reference white of 100 cd/m² at D65, reference black below 0.01 cd/m², the BT.1886 response, room illumination of 10 lux and a D65 background at about 10 per cent of reference white.

  Caveat: The recommendation says it is a guideline for practical implementation and is not intended to require absolute uniformity between facilities.

  Source: Recommendation ITU-R BT.2035: A reference viewing environment for evaluation of HDTV program material or completed programmes

• StandardStrong evidence

  ITU-R BT.2100-3 specifies a reference viewing environment for HDR with a neutral grey D65 surround at 5 cd/m², a display peak of at least 1,000 cd/m² and a black level of at most 0.005 cd/m².

  Source: ITU-R Recommendations BT.709, BT.2020 and BT.2100

• StandardStrong evidence

  EBU Tech 3320 version 4.1 defines a Grade 1 monitor as a measuring instrument for visual evaluation of image quality, used for camera control, colour grading and quality control, and requires its black level to be below 0.05 cd/m².

  Source: EBU Tech 3320: User requirements for Video Monitors in Television Production, version 4.1

• FactStrong evidence

  Dolby's grading guide recommends that the HDR and SDR monitors used together be of the same display technology, because monitors of different technologies may exhibit metameric differences.

  Source: Dolby Vision Color Grading Best Practices Guide, version 4.0

• Colourwise interpretationModerate evidence

  A picture viewed in a web browser is outside every one of these conditions, so a still or clip online can show the composition of a grade but cannot stand as evidence of its colour or contrast.

  Based on: The reference conditions fix display white, response, black level and surround; a browser on an arbitrary device controls none of them.

  Source: Recommendation ITU-R BT.2035: A reference viewing environment for evaluation of HDTV program material or completed programmes

Related questions

Can I grade on a calibrated consumer OLED television?

Many people check on one, and it is a fair guide to what viewers see. BT.2035 says consumer displays should not be used for professional evaluation, and the EBU's requirements bar automatic brightness limiters on Grade 1 and Grade 2 monitors, a feature many televisions rely on.

Why is the wall behind a grading monitor lit at all?

A screen in a black room looks more contrasty than the same screen in a home, and the eye tires. A dim neutral bias light fixes the eye's adaptation at a known level and colour, which keeps judgement stable through a session.

Is D65 always the white point for film work?

For television and streaming masters, yes. Digital cinema projection was standardised around a different, greener white, and theatrical grades are made in a projection room to that target or to D65 by agreement.

Related topics

Go further

Sources

• Recommendation ITU-R BT.2035: A reference viewing environment for evaluation of HDTV program material or completed programmes — International Telecommunication Union, Radiocommunication Sector (Official standard or government)
• ITU-R Recommendations BT.709, BT.2020 and BT.2100 — International Telecommunication Union, Radiocommunication Sector (Official standard or government)
• EBU Tech 3320: User requirements for Video Monitors in Television Production, version 4.1 — European Broadcasting Union (Official standard or government)
• Dolby Vision Color Grading Best Practices Guide, version 4.0 — Dolby Laboratories (Manufacturer technical documentation)
• Recommendation ITU-R BT.1886: Reference electro-optical transfer function for flat panel displays used in HDTV studio production — International Telecommunication Union, Radiocommunication Sector (Official standard or government)
• Report ITU-R BT.2408: Guidance for operational practices in HDR television production — International Telecommunication Union, Radiocommunication Sector (Official standard or government)

Reviewed 6 October 2026. Colourwise summarises its sources in its own words and does not reproduce standards text or proprietary colour data. Spotted an error? Tell us.