Some notes on monitor calibration

Root6 offers a calibration service primarily for CRT-based grade-1 broadcast monitors as many people who are serious about colour accuracy still regards a CRT as the gold standard. By default we work to the BBC standard with a white point at 80 Cd/m2 and a colour temperature of 6504K (AKA “illuminant D”) although we are aware that facilities that grade for film will set their monitors slightly dimmer (in the 60-70 Cd/m2) for better Delta-E performance.

1. Source material – we will bring test footage on videotape as this is still the lingua franca – if you don’t have a DigiBeta or HDCam playback deck then let us know.
2. We won’t make your monitor look ‘great’ rather we will make it correct – compliant with the standard. The whole point of accurate monitoring is to produce an honest display to shows good pictures only when the pictures are good. Remember – the person in the QC suite at the broadcaster/mastering facility will be looking at a calibrated monitor, not a ‘great’ monitor.
3. Hardware faults – calibration won’t fix a monitor that needs a trip to a workshop. If you crank the contrast knob and the pictures ‘blooms’ (changes size slightly) then your EHT regulation is poor. There are a few other faults that get progressively worse as a tube ages and you can’t calibrate-out these faults.
4. White levels – we often arrive in edit suites and find the whites set at twice what they should be (typ. 150 Cd/m2) because the room isn’t set up for grading and has too much ambient light. This is sub-optimal because at those light levels your eyes aren’t seeing any black detail and your monitor is likely out of its linear range and the fidelity in the whites is compromised. Remember, in grading brighter isn’t better!
5. Black levels – ambient lighting affects black levels noticeably. Please think about the lighting in your room so that we can set accurate blacks for the same environment you’ll be working in. We’ll show you how to re-set your blacks if you need to brighten-up the room (for a client viewing, for example).
6. LCDs, Plasma, projectors and other display types – We are often asked to match a projector to the grading CRT monitor which is fine but domestic LCDs and Plasma televisions are an order of magnitude brighter than grading levels and should be treated as client content monitors only.
7. Broadcast LCD monitors – The colour of newer ‘grade-1’ broadcast LCD monitors is governed by the colour of the backlight and as such doesn’t vary for the first 20-30,000 hours of use and generally leave the factory set correctly. Again, we can match these to the grading CRT but metameristic differences mean that we won’t set up an LCD in isolation.
8. Computer monitors – These are designed for displaying computer GUIs at much higher light levels than you would grade at – typically 200-300 Cd/m2 and so a correctly calibrated broadcast monitor next to an Apple Cinema display will look milky and dim. You couldn’t grade accurately off the Cinema Display that shows your FCP playback and so wanting to make your broadcast monitor match it is ultimately futile. Always treat your NLE’s playback display as content only, it isn’t colour or light-level accurate.