TV-BAY December 2012
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Colour monitoring for 3D or 2D - let’s get it right! by Steve Hathaway W e are spoilt for choice these days in cinemas or with television as there’s a plethora of factual and fictional entertainment. Flicking through the channels, the array of colours in programmes is even more bamboozling as broadcasters and programme makers do not seem to adopt the same colour standards despite the best efforts of colourists. However, is this a case of technology advancing faster than knowledge and production people encouraged to adopt the latest picture monitors at the behest of colour standards? This is a visual industry and there are colour standards for television to ensure that the interchange and display of video content is consistent, it’s called EBU- REC709, the standard that helps you to ensure that you’re getting it right. I stumbled upon The Gadget Show where the presenters were evaluating three well known brands of 55” Smart televisions. The objective was to be able to determine which television was the best and their well structured tests involved assessment of colour and movement artefacts. Sitting on the sidelines from afar it’s easy to think of other considerations that they could have taken into account such as rolling captions and crawling information bars, however they are really not a key part of the overall viewing experience unless you spend a lot of time watching the 24/7 scrolling tickers on Sky sports or BBC News channels. In doing a professional monitor assessment we would always recommend using a test signal or picture sequence that exercised the monitors in the same way and in recollection most people in the broadcast and film industries don’t do this assessment either! The presenters of the Gadget show each held different opinions on colour reproduction of the televisions and although having assessed the televisions with different criteria they were largely in agreement. Interestingly, branding seemed to be of little influence as the three brands where major high street brands whereas, in the broadcast industry branding is a significant factor. The consumer doesn’t have any objective measurement tools for establishing the performance of a television whereas the broadcast industry does have a strict set of criteria which are set out by the SMPTE and the EBU yet curiously these are disregarded in most cases. In London, which is considered by many as a major production centre for television and film industries our research indicates that there is only one post house which runs fully colour compliant, REC709 picture monitoring. It’s quite astonishing in an industry that trades entirely on communicating and entertaining with pictures, that colour standards are ignored. If Jeremy Clarkson were to comment upon this he’d probably explain it along the lines of you putting smelly chip fat in your diesel engine because you like the lady selling it and its cheaper even though your engine won’t last as long and your car will reek of yesterdays fry ups; anyway, BP’s green diesel fuel may be technically better but its over rated. Fortunately, in the broadcast industry, the future has been mapped out for a while. The colour standard for HDTV signals was mapped out as long ago as 1990 by the SMPTE and the EBU and like all futures, it’s based upon legacy and there are a raft of documents that set out today’s standards of technical performance and colour reproduction for broadcast LCD picture monitors. Unlike the presenters in the Gadget Show who made up their own criteria you don’t have to and choosing a monitor is very simple. Firstly, does the monitor display the correct colours, secondly is it free from motion artefacts and thirdly are the pictures in sync with the audio? Waveform, vectorscope, safe area marker, audio meters and the like are of lesser importance than colour. The custodians of the industry are the ITU, EBU and SMPTE and ITU-R Rec.709 is the international interchange colour standard for studios and broadcast television for HDTV signals. Charles Poynton in his book called Color Science for Video points out that all physical devices have their own tolerances and uncertainties but at least by achieving a common standard of colour reproduction such as REC709 the picture interchange will be visually the same. This article is not intended to go into depth but to provide the reference points for the colour and metrics of 46 | TV-BAY MAGAZINE TV-BAY072DEC12.indd 46 07/12/2012 15:14