QUALITY OF LIGHT
Without light, it would be impossible to view the world around us. Light illuminates objects for us to see and the spectrum emitted by a light source provides the colour in these objects. Variants of color offers advantages for different lighting applications. The lighting industry uses several tools-Kelvin, CCT, CRI, R-values and TM-30-to describe colour characteristics and light quality.
With the development of LED technology the quality of electric light has been changed forever. LED sources illuminate objects for us to see and now feel the full range of colours within these objects. New lighting technology takes advantage of a wide variety of colours to meet your and your customers application needs.
THE CORRELATED COLOR TEMPERATURE SCALE
The Kelvin based CCT (Correlated Colour Temperature), is a scale used in lighting to measure the colour temperature of a luminaire. It puts specifics to the description of the appearance of white light as "warm", "neutral" or "cool" (CCT chart, below).
The colour chosen for an application may vary based on the use of the space and the material being illuminated. For example, "warmer" light is very popular in residential applications while "cool" light is more prevalent in commercial and industrial spaces. We offer a wide variety of options to meet your needs for any lighting application.
CORRELATED COLOUR TEMPERATURE(CCT) LIGHT RANGE COMPARISON CHART
General Lighting offers a wide range of products and solution to illuminate your space.
| METRIC | SCALE | DESCRIPTION |
|---|---|---|
| Fidelity Index (Rf) | 0-100 |
A measurement of fidelity comparable to CIE CRI (Ra) but averages the values of 99 colour samples instead of 8. A higher value typically provides a more accurate rendition of colour in comparison to a natural light source. |
| Gamut Index (Rg) | 60-140 |
Gamut (Rg) measures the average hue and saturation (chroma) shift of a light source using 99 colour samples. A value of 60-99 indicates aver-age desaturation. A value of 101-160 indicates average increased saturation. |
| Color Vector Graphic | Visual |
The Color Vector Graphic shows the relative saturation of multiple hues. It’s important as it quickly conveys what types of colors are more or less saturated. |
| Fidelity Skin (Rf,skin) | 0-100 |
Fidelity Skin (Rf, skin) is an average of CES15 and CES18 skin tones. A higher value typically pro-vides natural looking ‘skin tones’. |
| Fidelity Red (R9) | 0-100 |
Fidelity Red (R9) derives from a single, saturated, red color sample. A higher value is important for illuminating red surfaces, wood grains and skin tones. |
| CIE CRI (Ra) | <0-100 |
CRI (Ra) is a legacy measurement of Fidelity using 8 colour samples and with an undefined lower scale. A higher value typically provides more accurate average rendition of colour. Comparably, TM-30 fidelity (Rf) is a much more im-proved metric for accurate colour rendition than CRI (Ra). |
COLOUR RENDERING INDEX
A Colour Rendering Index (CRI ) is the most useful measure of a colour characteristic of a light source, which is the measure of the ability of a light source to reveal the colours of various objects faithfully in comparison with an ideal or natural light source like the sun (CRI 100) or an incandescent bulb.
To avoid under or over saturated objects and mute colors, CRI must be in a range of 80-98 CRI, specially in retail, food and art environments, making surfaces appear colourful, vibrant and natural.
CRI is calculated using eight reference samples in CIE 1995 colour space, called R-values, the highest values are very important for illuminating skin tones, retail object and food. Our LED are made to deliver highest R-values.
A BRIEF LOOK INTO TM-30:
IES TM-30-15 is a new color rendering system that remedies flaws/limitations of CRI, providing complementary and more detailed information that benefits both specifiers and manufacturers. The much wider range of colors is a more accurate reflection of the real world – allowing you to show detailed colors for skin tones, wood grains, decorative art, furnishings, merchandising and more. While CRI isn't going anywhere soon, it's important to familiar-ize yourself with the new TM-30 metrics as they will become more common in years to come.
TM-30 COLOR CHART
TM-30 measures against 99 color samples, all used to provide Fidelity (Rf), Gamut (Rg) and Color Vector Graphics.
CRI VS TM-30 RENDERING TOOLS
CIE 13.3-1995(CRI/Ra)
• Last major update was in 1976
• 8 main color samples (Ra), 6 special samples
• Measures Fidelity (Ra) only
IES TM-30-15
• Released in 2015
• 99 color samples
• Measures Fidelity (Rf), Gamut (Rg) and includes Color Vector
A combination of TM-30's Fidelity (Rf), Gamut (Rg) and Colour Vector Graphic will help further clarify beyond the typical CRI metric how a test source compares to a reference source.
Television Lighting Consistency Index (TLCI)
TLCI: The Television Lighting Consistency Index averages 24 colors from the MacBeth chart (which is now owned by X-Rite and is called the X-Rite ColorChecker). The maximum value is 100, with100 being best.
(Note: colors for TLCI are named below.)
PERFECT COLOR CONSISTENCY
Perfect color consistency with SDCM (Standard deviation of color matching) in only 3-step and one bin as standard supply.
