Reference Monitor for Colour Grading: India Buying Guide

A reference monitor for colour grading is a display built to show the signal exactly as the standard defines it: correct gamut, correct gamma or EOTF, correct white point, and the same result every day. A consumer or prosumer screen can look good, but it is tuned to please, not to measure. If your grade has to survive broadcast QC, an OTT HDR delivery or a client review, you need a display that holds calibration, takes SDI, and can be checked against a probe.

Whatever name you search for, reference monitor or color grading monitor, the requirements are the same. This guide explains what separates a true reference monitor from a nice-looking screen, what to check before you buy, and how to set up a grading suite around it. We use the Flanders Scientific XMP and DM series as worked examples, with every specification taken from flandersscientific.com.

What a reference monitor actually does

A colourist makes thousands of small decisions based on what the screen shows. If the screen is wrong, every decision is wrong in the same direction, and the error only appears when the file plays somewhere else. A reference monitor exists to remove that variable. It has four jobs:

Accurate tone response. For SDR HD work the reference is ITU-R BT.1886, which specifies a gamma 2.4 transfer function for flat panel displays used in HDTV studio production. For HDR, ITU-R BT.2100 specifies two transfer functions: PQ (SMPTE ST 2084) and HLG.
Accurate gamut. The monitor must map the signal into the right colour space: Rec.709 for HD broadcast, DCI-P3 for digital cinema, and Rec.2020 as the container for UHD and HDR.
Stable calibration. The picture should measure the same next month as it does today, and you should be able to verify that with a probe.
Professional signal handling. SDI inputs, correct reading of the signal format, loop-through outputs and built-in scopes, so the monitor fits into a facility signal chain.

Calibration stability and how you verify it

Every display drifts over time. The question is how easily you can measure the drift and correct it. Flanders Scientific states that all FSI monitors ship pre-calibrated from the factory, and that the XMP, XMP C and DM series support GaiaColor Direct Connect Volumetric AutoCal. A supported probe plugs straight into the monitor, and the monitor profiles itself without a computer.

The important word is volumetric. FSI explains that, unlike white-balance-only auto calibration, GaiaColor AutoCal uses volumetric data to target every selectable gamut, colour temperature and EOTF on the monitor. 3D and 1D LUTs are calculated for whichever selection you make, so switching from Rec.709 gamma 2.4 to P3 PQ does not mean running a new calibration.

On the XMP series, FSI adds GaiaColor Analyzer, a built-in QC tool. With a compatible probe it produces an on-screen calibration report in as little as 60 seconds, keeps the two most recent reports in memory, and can export them as PDF through the free IP Remote Utility. For a post house this is the practical answer to “is the monitor still on target?” before a client session.

FSI also supports third-party calibration with Calman, LightSpace and ColourSpace. Its calibration page notes that Calman can only be used for SDR calibration with FSI monitors, and that colorimeters are not display-type agnostic: each needs a matrix for the display technology being measured. Listed AutoCal probes for the XMP series include the CR100, K10A, K80, CA210 and CA310 (10mm), CA410 and the i1D3DS OEM. FSI also offers free recalibration for the life of the monitor at its service centres in Atlanta, Tessenderlo (Belgium) and Andover (UK), with the customer paying shipping, and its calibration page lists an on-site calibration partner in India.

SDI inputs and signal handling

SDI is the professional video interface defined by SMPTE. All SDI variants use coaxial cable with 75 ohm BNC connectors, and the 6G-SDI and 12G-SDI standards were published in 2015. 12G-SDI carries a 2160-line UHD signal over a single cable, which simplifies a grading room because one coax run feeds the monitor from the video I/O card.

On the XMP310, FSI lists 4 x 12G/6G/3G/HD-SDI inputs, 4 clean loop outputs and 4 processed MON outputs. The monitor reads the payload ID (VPID) in the SDI signal and sets itself for 4:4:4 or 4:2:2, 10 or 12 bit, RGB or YCbCr, with a manual override if the payload ID is missing. The processed outputs can send a quarter-sample downconverted 3G or 1.5G signal, so a UHD feed can drive a downstream HD monitor or scope without a separate converter.

The DM series works at HD. The DM242, for example, has 2 x 3G/HD/SD-SDI inputs, 1 DVI-D and 1 DisplayPort, with 2 clean and 2 processed SDI loop outputs. FSI notes that DM monitors can cross-convert DisplayPort, HDMI or DVI signals to SDI for output.

Gamma, EOTF and gamut selections

A reference monitor lets you choose the transfer function and gamut to match the deliverable, rather than applying one fixed look. The XMP310 lists gamma 1.0, 1.8, 2.0, 2.2, 2.35, 2.4, 2.6 and 2.8, plus PQ (ST 2084), HLG and custom. Its colour space selections are Rec.709, DCI-P3, Rec.2020 and custom, with FSI noting the Rec.2020 selection covers about 80% of the Rec.2020 gamut on the XMP310. White point options include 6500K, 6000K (P3-D60) and 6300K (P3-DCI).

The DM242 offers SMPTE-C, EBU, Rec.709, Rec.2020 emulation, DCI-P3 and user colour spaces, with the same gamma range from 1.0 to 2.8. FSI is clear that its Rec.2020 emulation does not fully cover the Rec.2020 colour space.

Each XMP input can carry its own gamut, EOTF, white point and luminance settings. Combined with Quad View mode, this lets you watch an HDR and an SDR version of the same shot side by side on one screen.

HDR and SDR: mastering versus preview

PQ, published as SMPTE ST 2084, represents luminance from 0 to 10,000 cd/m2. No current display reaches that ceiling, so HDR monitors are judged on how much of the range they can show accurately. FSI splits its range into two HDR tiers:

HDR Mastering: XMP270, XMP270C, XMP310, XMP310C, XMP550, XMP550C, XMP551 and XMP651. FSI says these qualify as Dolby Vision mastering monitors and have a peak luminance rating of at least 1,000 cd/m2.
HDR Preview: DM160, DM211, DM220, DM231 and DM242. These offer HLG, PQ with a hard clip near peak, and PQ with soft highlight roll-off, for production and QC rather than final HDR finishing.

FSI also makes a point about contrast that matters when comparing displays. Global dimming LCDs are often quoted with high sequential contrast, where peak white and black are measured at different times. For HDR grading, what matters is simultaneous contrast: bright highlights and deep shadows in the same frame. FSI states that the XMP’s per-pixel QD-OLED panel avoids the haloing and raised blacks that local dimming LCDs show around bright objects.

FSI XMP and DM models compared

The table below lists published specifications for the models most relevant to a grading suite. For the full range, see our FSI range and buying guide.

Model	Size and resolution	Panel	Peak luminance	Contrast	SDI inputs	HDR tier
XMP550	55″, 3840×2160	QD-OLED, 10 bit	~2,000 cd/m2 at L20	~4,000,000:1	4 x 12G/6G/3G/HD	Mastering
XMP310	31.5″, 3840×2160	QD-OLED, 10 bit	~1,000 cd/m2 at L18, ~250 full screen	~1,500,000:1	4 x 12G/6G/3G/HD	Mastering
XMP270	26.5″, 3840×2160	QD-OLED, 10 bit	~1,000 cd/m2 at L18	~1,500,000:1	4 x 12G/6G/3G/HD	Mastering
DM242	24″, 1920×1200	Wide gamut W-LED LCD, 10 bit	400 cd/m2	1800:1	2 x 3G/HD/SD	Preview
DM160	15.6″, 1920×1080	RGB OLED, 10 bit	400 cd/m2 full screen	1,000,000:1	2 x 3G/HD/SD	Preview

FSI lists the XMP550’s Rec.2020 selection as covering about 90% of the Rec.2020 gamut, against about 80% for the XMP310 and XMP270. For a deeper look at the two series, read our XMP vs DM guide.

Scopes and client monitor setups

Built-in scopes do not replace the scopes in your grading software, but they confirm what is arriving at the display. The XMP310 has a real-time waveform and vectorscope that work with 4K, UHD and HDR signals, with the waveform graticule in percentage or PQ nits. The waveform takes six colour-coded thresholds, and a PQ-based false colour mode switches to a nits scale when the monitor is in PQ. DM series monitors have real-time waveform and vectorscope that update every frame, an HDR waveform view for PQ signals, and ScopeStream, which sends the scopes to a computer over the network.

The client monitor is a common weak point. FSI notes that matching a 31-inch mastering display to a larger screen has traditionally been difficult because the two sizes used different display technologies. FSI positions the XMP550 as a reference grade display large enough for both colourist and clients to view. It also states that the XMP310, XMP550 and XMP650 share the same QD-OLED panel technology and colour management system, which helps a 31.5″ grading monitor and a 55″ client display stay consistent. FSI adds that the XMP series has its widest viewing angle and least off-axis shift of any FSI display, which helps when clients sit away from the centre line.

Setting up a grading suite monitor

A reference monitor is only as accurate as the room around it. The standards bodies publish clear guidance.

Viewing environment for SDR

ITU-R BT.2035 defines a reference viewing environment for evaluating HDTV programmes. It specifies:

Room illumination of 10 lux.
A background behind the monitor at D65 chromaticity.
Background luminance of about 10% (plus or minus 2%) of the monitor’s reference white.
Reference white of 100 cd/m2 and reference black below 0.01 cd/m2, with a D65 white point at x 0.3127, y 0.3290.
A design viewing distance at which two adjacent pixels subtend 1 arc-minute at the eye.

Viewing environment for HDR

For HDR, Rec.2100 calls for a surround of 5 cd/m2, neutral grey at D65. Light Illusion’s viewing environment guide summarises the reference room as a D65 surround covering 90 degrees horizontal and 60 degrees vertical, with average room illumination at or below 5 nits. It also notes that many SDR colourists still prefer the older 10% surround, nominally 10 nits for a 100 nit display.

Practical steps

Paint the wall behind the monitor a neutral grey and remove windows or block them fully.
Fit a bias light behind the monitor. A 6,500K source matches the D65 white point, and a colour rendering index of at least 90 is recommended. FSI sells Ideal-Lume bias lights for this purpose.
Set the surround luminance to the standard for your main deliverable: about 10% of reference white for SDR, 5 cd/m2 for HDR.
Let the monitor warm up, then run AutoCal or your third-party calibration with a probe that has the right matrix for the panel type.
Run a QC report before client sessions and keep the history.

What to check before you buy

Your deliverables. Rec.709 SDR broadcast work can be done on a DM series monitor. If you deliver HDR for OTT platforms, look at the HDR Mastering tier.
SDI bandwidth. UHD over a single cable needs 12G-SDI. HD-only suites can work with 3G-SDI.
EOTF and gamut menu. Confirm BT.1886 gamma 2.4, PQ and HLG, plus Rec.709, P3 and Rec.2020 selections, and check the published Rec.2020 coverage figure.
Calibration path. Check which probes the monitor supports for auto calibration and whether your preferred software can write its LUT format.
Room fit. Size, weight, mounting and viewing angle for your suite, plus a plan for the client display.
Local support. When choosing a colour grading monitor in India, buy through an authorised channel so warranty and calibration support stay straightforward.

Where to buy Flanders Scientific in India

Colo Exim in Mumbai is the official distributor of Flanders Scientific monitors in India. We can help you match an XMP or DM model to your deliverables, suite size and signal chain, and advise on probes and calibration. Make an inquiry or call us on +91 93204 96801.

Frequently asked questions

Why do I need a reference monitor for colour grading instead of a good consumer display?

A reference monitor is built to reproduce the standard exactly: the correct EOTF such as BT.1886 gamma 2.4, PQ or HLG, the correct gamut and a D65 white point, and to hold that calibration over time. It also takes SDI and can be verified with a probe. A consumer display is tuned for appealing pictures, so grades made on it can look different on other screens.

What is the difference between FSI’s HDR Mastering and HDR Preview monitors?

FSI’s HDR Mastering monitors (the XMP270, XMP310, XMP550 and related XMP models) qualify as Dolby Vision mastering monitors and have a peak luminance rating of at least 1,000 cd/m2. HDR Preview monitors in the DM series offer HLG and PQ preview modes with clipping or roll-off and are designed for production and QC rather than final HDR finishing.

Do I need 12G-SDI on a colour grading monitor?

If you grade in UHD and want to feed the monitor over one cable, yes. 12G-SDI carries a 2160-line signal on a single coax. The FSI XMP series has four 12G/6G/3G/HD-SDI inputs. For HD-only work, 3G-SDI as found on the DM series is enough.

How bright should the wall behind my grading monitor be?

ITU-R BT.2035 recommends a D65 background at about 10% of the monitor’s reference white for SDR evaluation, with room illumination of 10 lux. For HDR, Rec.2100 recommends a 5 cd/m2 neutral grey surround at D65. A 6,500K bias light with a high colour rendering index is the usual way to achieve this.

How often should a reference monitor be calibrated?

Measure it regularly rather than following a fixed calendar. On FSI XMP monitors, the built-in GaiaColor Analyzer produces a QC report in about a minute with a supported probe, so you can track drift and run GaiaColor AutoCal when results move off target.

Can I calibrate an FSI monitor with Calman or ColourSpace?

Yes. FSI supports Calman, LightSpace and ColourSpace alongside its own GaiaColor AutoCal. FSI notes that Calman can only be used for SDR calibration on its monitors, and that colorimeters need a matrix for the display technology being measured.