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Photopic and scotopic vision

Our eyes are designed to respond to the full spectrum of sunlight and not to selected areas.

The sensitivity of the rods in your eye is known as the photopic response and refers to colour vision and the perception of fine detail.

The sensitiivity of the rods in your eyes is known as the scotopic response and refers to vision under conditions of low level light intensity - so called 'night vision'.

Photopic sensitivities are at a maximum in green light at about 555 nm which is the wavelength at which the cones in our retina are most receptive. However scotopic sensitivities peak about 50 nm lower in the blue-green region of the spectrum at 507 nm, where the rods are most receptive.

 
 
 
© Keith Gibbs 2011