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Physics
Colored light and vision
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Change the wavelength, add a filter and mix red, green and blue light to see which color the eye perceives.
Yellow
Wavelength: 580 nm
Brightness: 100%
Single-color light at 580 nm belongs to the yellow part of the spectrum.
380 nm780 nm
The light has one wavelength: 580 nm.
- White mark: the light's wavelength
Model notes
- The human eye has three types of cone cells, most sensitive to short (blue), medium (green) and long (yellow–red) wavelengths. The brain compares how strongly each type is stimulated to produce a color sensation. The simulation does not compute the response of each cone type; it shows the equivalent color directly.
- Single-color yellow light (about 580 nm) and a suitable mix of red + green light stimulate the three cone types almost identically, so we perceive the same yellow. Here, 580 nm light and red 100% + green 100% show the same color. Magenta (red + blue) matches no single wavelength.
- Screen colors are only approximations within the sRGB gamut: a screen cannot reproduce the exact color of single-wavelength light, especially violet and deep red. Wavelength colors use a piecewise-linear approximation (Bruton); the boundaries between the seven color names are approximate conventions because the spectrum changes continuously.
- Each photon dot stands for very many photons; the number of dots per second is not the real number of photons. In Photons view the light is slowed down so it takes about 1.2 seconds to reach the eye, and the bubble changes only when the new light arrives. This is an illustration: real light crosses 1 m in about 3 billionths of a second.
- The filter here transmits most strongly at its own wavelength, less and less further away, and blocks everything 35 nm or more away. Real color filters usually pass a wider band. White light through the filter is still shown at full brightness so the color is easy to see, although in reality only a small part of the energy gets through.
- The light's white light is treated as an even mixture of all wavelengths from 380 to 780 nm. The three lights use the screen's red, green and blue primaries, not specific wavelengths; their intensities add like real light before being converted to display colors. The head, brain and optic nerve drawings are illustrations, not to scale.