' Film & Television - National Photonic Ltd.

Film & Television

Spectrum Genius-Studio [SGS] follows the standards of Television Lighting Consistency Index (TLCI) set up by the European Broadcasting Union (EBU). The TLCI metric (Television Lighting Consistency Index) was developed to address the shortcomings of traditional CRI measurement techniques.
Because cameras interpret light differently to how the human eye perceives it, a TLCI spectrometer provides a more accurate prediction of the colour rendering characteristics of film and studio lighting.


  • Reduce time to set studio lighting
  • Minimise post-processing
  • Television Lighting Consistency Index (TLCI) established by European Broadcasting Union (EBU)

Recommended products for colourists, gaffers, and technicians

The Spectrum Genius Studio (SGS) APP for iPad is a TLCI spectrometer that provides users with the ability to get all the TLCI information easily and quickly.  When used with the Lighting Passport Spectrometer, “Spectrum Genius Studio (SGS)” allows professionals such as producers, colourists, gaffers, and technicians to get full and detailed information about the TLCI of a specific light source or the entire set up.

What is the Television Lighting Consistency Index (TLCI) metric?

The TLCI value is an index on a 0-100 scale that is a composite of multiple parameters.  Television and film studio production often adopts a TLCI > 90 as a minimum starting point, providing cinematographers and gaffers a fast, accurate method to quantify lighting and avoid spending a lot of time and effort on extensive testing while minimising the amount of post-processing required.

Simply select TLCI as the reference standard and SGS will compare your measured light source with the TLCI Standard values and tell you how much your measured light differs from the Standard.

In addition to TLCI, the “Spectrum Genius Studio (SGS)” APP also provides several other useful parameters such as CRI, CQS, and CCT.

What is the Television Lighting Matching Factor (TLMF)?

Television Lighting Matching Factor (TLMF) allows users to set the data of their preferred Fresnel or Flood Light as the reference point. When users select the TLMF reference as the benchmark, the Assessment Index, Colour-Checker Chart, Colourists Advice, and Spectrum Reference will also use that benchmark to run the calculation.

Broadcasters around the world such as BBC, NBC, CNN, Disney and ITV recommend that TV professionals use TLCI as their light standard measuring parameter. With the TLCI, colourists can do their job faster at time of shoot and minimise post-production costs.

What is the Colour-Checker Chart?

The Colour-Checker Chart shows the colour differences on the screen between the reference light source and the measured light source.

The colour patch provides a “visual” of the difference between the “Reference Light Source” and “Measurement Light Source.” Also, the Q value at the bottom of each colour patch quantifies the percentage of “similarity” between the Reference and Measurement light sources.

TLCI Colour Checker

Std Magenta

85 to 100 Excellent colour quality.  Errors sufficiently small that colourist or lighting engineer may consider not making a correction or make only minor adjustments.
75 to 85 A colourist would likely wish to make some adjustments to correct colour performance but should be able to quickly achieve an acceptable lighting set-up.
50 to 75 A colourist or lighting engineer would likely have to make large adjustments to the camera or use gels to correct for the luminaire’s colour deficiencies. Experienced professionals will be able to achieve an acceptable result although this is often a time consuming exercise.
25 to 50 The colour rendering of the luminaire is poor, requiring the services of an expert colourist or lighting engineer to make significant adjustments. The results would be unlikely to meet broadcast standard.
0 to 25 The luminaire is a poor choice no matter what adjustments are made to the camera at time of shooting.  The  colourist or lighting engineer would struggle to adjust for the camera on site or for post production. Results would almost certainly be unacceptable for TV and the broadcasting industry in general.

What does the Colourists Advice provide?

A TLCI spectrometer with Colourists Advice offers great convenience for gaffers, camera operators, and colourists. Camera operators can use this guide to adjust the camera when needed, while visual effect colourists can either enhance or decrease the lightness, chromaticity, and hue in each of the 12 colour sectors to help achieve the end result desired.

In the Colourists Advice table in the above right the “+” and “–” values indicate the magnitude of the corrections required.  The larger the value, the harder it is to correct. (The maximum is “ +8 ” and the minimum is “ -8 .”)

Recommended TLCI Spectrometer products for colourists, gaffers, and technicians