VS - Lighting Systems - Lighting - 998542

CIE chromatic diagram

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Cy

520

530 nm

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540

C.I.E. 1931 simplified chromaticity diagram

510

5.2.2. Light colour

550

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560

5.2.2.1. The colourimetric graph: CIE grid

Yellowish Green

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Green

570 nm

500

Yellow Green

The International Commission on Illumination also known as the CIE from its French title is an international standardization body, it is devoted to worldwide cooperation for lighting, colour and vision purposes. The CIE has defined a standard grid that permits to specify light sources colours: the CIE grid The CIE grid represents all of the colours that are visible to the average person. l The edges of this diagram corresponds to the so- called monochromatic lights. Monochromatic colours are specified by their unique or preponderant colours and wavelengths in nanometres (nm). l Chromatic lights are located in the interior of this diagram. Chromatic colours are specified with the so-called X and Y coordinates. l White colours are located in the centre of this global chromaticity diagram. As “whites” are at the border of several chromatic colours, there is a large pallet of white colours. White colours are defined in the CIE grid, either by their “colour coordinates” or their so called “colour temperatures”. l Colour coordinates x,y are defined on the CIE chromaticity diagram l Colour temperature (in Kelvin: K) is another way to characterize white illuminants. Colour temperatures over 5000 K are called cold colours (bluish white), lower colour temperatures (2700 –3000 K) are called warm colours (yellowish white through red). 5.2.2.2. White colours

Greenish Yellow

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580

Yellow

Orange Yellow

590

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Orange

600 nm

Bluish Green

Reddish Orange

610 nm

Shades of white

640 630 nm 620

Pink

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490

Red

650

770

Purplish Pink

Greenish Blue

Purplish Red

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Reddish Purple

Purple

Blue

480

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Violet

Purplish Blue

470 nm

460

450

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440430 380

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Monochromatic colours

Chromatic colours

White colours

Focus on white colours CIE 1931 x,y chromaticity diagram

0.46

2700K

0.44

3000K

3500K

0.42

4000K

0.40

4500K

5000K

Y

0.38

5700K

0.36

6500K

0.34

0.32

0.30

0.28 0.28 0.30 0.26 0.32 0.34 0.36 0.38 0.40 0.42 0.44 0.46 0.48 0.50 0.52

X

l Day light temperature ≈ 6500 K l LEDs > 4500 K

l Xenon lamps ≈ 4300 K l Halogen lamp ≈ 2800 K l Candle flame ≈ 1850 K

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