VS - Lighting Systems - Lighting - 998542

5. The lighting system: what is light?

Our “eye‘s preferred colour” in day time is Green (555 nm)

5.1. The human eye 5.1.1. The eye sensitivity

MAX.

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SPECTRAL EYE SENSITIVITY V( λ )

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The eye is a sensor, it is able to sense a small portion of all electromagnetic radiations. Colours are the way human eyes and brains can distinguish different wavelengths of light.

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Bluish colors

Reddish colors

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Some colours are better perceived than others, this is due to the structure of the human eye.

Relative eye sensitivity

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MIN.

MIN.

The visible wavelengths are usually between 400 nm and 700 nm, and the sensitivity of the human eye to wavelengths outside this range drops dramatically. 5.1.2. Day and night-time visions Human eyes behave differently at night compared to daylight. The sensitivity of the human eye to colours strongly depends on whether it is light or dark.

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Color wavelength (nm)

Night-time

• Peripheral field of view. • Detection of movements and changes. • Not colour sensitive.

In dark conditions, a whiter light (bluer in the spectrum) improves visibility.

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