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No. Plants reflect green to balance luminosity extremes. Green is by far the most luminous color in the visible spectrum with dark purple being the least lumin

No. Plants reflect green to balance luminosity extremes. Green is by far the most luminous color in the visible spectrum with dark purple being the least luminous. Plants that reflect purple absorb the most visible light and can produce the most sugars. Most plants must undergo a chemical transition to shift from production to dark mode and by choosing to reflect green maximum energy production is sacrificed for internal chemical stability.

cbcivyxt 3y ago
[dead]
kalium-xyz 3y ago
Whats the mechanism here?
- austin-cheney 3y ago
  I found this which seemed informative: http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Why-did-chlorophyl-evolve-to-be-green-as-opposed-to-black.pdf http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Why-did-ch...
- bhewes 3y ago
  C02 levels. We use C02 to turn our weed buds purple.
_nalply 3y ago
> most luminous color What does luminous mean exactly in this context? I know that our eyes are most sensitive to green. For example a green LED needs less power to seem as bright as a red LED. But our eyes don't matter in this subject. So I am scratching my head about what you mean that green is the most luminous color?
- MayeulC 3y ago
  I think this is the color (wavelength) that corresponds to the sun's emissivity peak (irradiance in W/m²). The fact that our eyes are most sensitive to green is probably not an accident, but is it due to the color of leaves, or is it due to sunlight?
- austin-cheney 3y ago
  Here is the math used by W3C for computing acceptable contrast: https://www.w3.org/TR/WCAG20/#relativeluminancedef https://www.w3.org/TR/WCAG20/#relativeluminancedef I suspect luminosity to mean percentage of brightness for a given frequency from a total light source assuming white light. For a more precise definition I would look to physics.
  - buildartefact 3y ago
    That’s for sRGB, which as for most colour spaces is defined relative to CIE XYZ, which is itself defined in terms of the perception of a “standard human observer”. In XYZ, the Y coordinate is the luminance (brightness) of the colour and that first equation is computing Y from the RGB value

cbcivyxt 3y ago

[dead]

kalium-xyz 3y ago

Whats the mechanism here?

austin-cheney 3y ago
I found this which seemed informative: http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Why-did-chlorophyl-evolve-to-be-green-as-opposed-to-black.pdf http://www.esalq.usp.br/lepse/imgs/conteudo_thumb/Why-did-ch...
bhewes 3y ago
C02 levels. We use C02 to turn our weed buds purple.

_nalply 3y ago

> most luminous color What does luminous mean exactly in this context? I know that our eyes are most sensitive to green. For example a green LED needs less power to seem as bright as a red LED. But our eyes don't matter in this subject. So I am scratching my head about what you mean that green is the most luminous color?

MayeulC 3y ago
I think this is the color (wavelength) that corresponds to the sun's emissivity peak (irradiance in W/m²). The fact that our eyes are most sensitive to green is probably not an accident, but is it due to the color of leaves, or is it due to sunlight?
austin-cheney 3y ago
Here is the math used by W3C for computing acceptable contrast: https://www.w3.org/TR/WCAG20/#relativeluminancedef https://www.w3.org/TR/WCAG20/#relativeluminancedef I suspect luminosity to mean percentage of brightness for a given frequency from a total light source assuming white light. For a more precise definition I would look to physics.
- buildartefact 3y ago
  That’s for sRGB, which as for most colour spaces is defined relative to CIE XYZ, which is itself defined in terms of the perception of a “standard human observer”. In XYZ, the Y coordinate is the luminance (brightness) of the colour and that first equation is computing Y from the RGB value