There will be plenty of LED movie lights on show at NAB 2015 and no doubt many of you will be there studying their feature sets, the quality of their manufacture and the strength of their output. But what the industry has lacked until recently was a reliable, contemporary index for rating the quality of the light they produce.
Former BBC camera tester Alan Roberts stopped up to the challenge and created a new testing index, TLCI, to replace CRI, the old light color index. CRI stands for Color rendering index and is based on the way the human eye resolves colors trichomatically, as a combination of red, green and blue.
But camera sensors are a far cry from the human eye and Mr Robert’s testing methodology takes that into account. How is amply covered in the interview that Dan Chung of News Shooter recorded with him during BVE 2015 in the UK in late February.
Why can be found in two online articles:
- ‘Practical Spectroradiometry, An Introduction for uses of the Television Lighting Consistency Index’
- ‘Current TLCI Results as supplied by Alan Roberts’ at The Guild of Television Cameramen’s website.
Those articles and News Shooter’s interview follow on from a news item published by UK LED light manufacturer Rotolight Inc, ‘Rotolight Scores Highly in TLCI Test!’ The big takeaway from this article is that two Rotolight products ranked high in Mr Roberts extensive TLCI of all the LED lights he could obtain.
He found that the Rotolight NEO scored 85 and the Rotolight Anova Bi Colour V2 came in at 86. Under the TLCI system, a score of 85 or higher is “ideally suited for professional television/broadcast use”. Rotolight’s RL48-B LED lights ranked at 72. According to the TLCI chart published by the Guild of Television Cameramen, however, the Neo achieved scores of 90, 91 and 91 again when tested at color temperatures of 3200K, 3800K and 5600K. [bctt tweet=”Are your LED lights up to scratch colorwise? Ex-BBC color expert creates new test index, TLCI.”]
The performance of LED lights made by Rotolight, and the many others tested, is very encouraging. When LED lights began hitting the local market in a big way, I studied all that I came across at trade shows and noticed a distinct green tinge to many all of them as well as other anomalies. I chose to invest in some Rotolight RL-48-Bs then due to their relatively clean color rendering compared to the rest on show.
Now that we have the benefit of the TLCI and Mr Roberts’ dedicated testing work, choosing new lights is going to be a whole lot easier and based on contemporary science and technology.
BVE 2015: How accurate are your LED lights? Alan Roberts tests
Via Vimeo Description:
At BVE we had a chance to sit down with him and discuss some very significant testing that he has been doing on lights. Dissatisfied with the old CRI index which manufacturer’s commonly quote when talking about the accuracy of lights, he set out to create a better way to evaluate different light sources. Based on research done by old colleagues at the BBC, he has created a new way to test lights and compare them scientifically.
For the full story go to newsshooter.com
(cover photo credit: snap from the video)