What TLCI Means for Still Photography With LEDs

Television Lighting Consistency Index:  In November 2012 the European Broadcasting Union’s Technical Committee approved a recommendation designed to give technical aid to broadcasters who intend to assess new lighting equipment or re-assess the colorimetric quality of lighting in their television production environment.

LED lighting gear’s origin are in the world of television and still photographers have adapted the technology to work for us. It makes sense when you think about it, the sensor technology used in today;s digital cameras originated from  television cameras.

sarah.tlciWhich brings me to one of the first questions  people ask about my using LED lighting for portraits: “Isn’t the color bad?” Nope. The color response curves of video and still photography sensors are different than our eyes and are processed differently. I’ve written here about Color Rendering Index and color temperature. CRI is a quantitative measure of the ability of a light source to faithfully reveal the colors of objects  compared to an ideal light source.

TLCI uses a method similar to CRI by comparing a standard set of colors under a test light with that from a perfect black body light source or daylight. Like CRI, the colors are mathematically modeled so the test can be run using software that  contains an average of a many (television) cameras response that’s an average of many cameras. Unlike CRI that does not indicate the apparent color of the light source, the TLCI test uses multiple color temperature sources producing a number or index ranging from 0 – 100, with a perfect light source having a TLCI of 100. In practice any light source that has a TLCI of 85 or higher will usable for still photography with little or no correction.

Neo1As time goes by I think more and more manufacturers will integrate this measurement into their specifications. Take Rotolight’s NEO: I just finished a review of the lights you can read in the January, 2016 issue of Shutterbug that’s on newsstands now. NEO has a TLCI of 85, which amount to color errors so small that whatever Photoshop, Lightroom or software color correction tool you prefer would not need correcting.

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Author: Joe Farace

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