Physical parameters define colors like the pigment primaries

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Discussion Overview

The discussion revolves around the physical parameters that define colors, specifically focusing on pigment primaries (red, blue, yellow) and their mixtures, as well as light primaries. Participants explore the relationship between wavelengths, atomic structure, and the perception of colors.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • Some participants suggest that the wavelength of light determines its color, while others indicate that atomic structure or quantum mechanics may also play a role in defining the color of pigments.
  • A participant questions the assignment of specific frequencies to primary colors and seeks to understand how secondary colors arise from combinations of primary frequencies.
  • There is a suggestion that the perception of colors, such as green from yellow and blue, is influenced by the biology of the eye, particularly the function of cones and rods.
  • One participant challenges the idea that colors can be defined solely by blackbody radiation, while another suggests that the blackbody spectrum of the sun may have some relevance.
  • There is confusion expressed regarding whether the wavelengths of blue and yellow light combine to create green light, with participants noting that perception may differ from physical properties.
  • A later reply introduces the concept of phototransduction in the eye as a mechanism for color perception, though the participant expresses uncertainty about their authority on the topic.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the definitions of colors or the mechanisms behind color perception. Multiple competing views and uncertainties remain regarding the relationship between wavelengths, perception, and the physical properties of colors.

Contextual Notes

Limitations include unresolved definitions of primary and secondary colors, dependence on biological interpretations of color perception, and varying interpretations of the role of blackbody radiation in color definition.

Loren Booda
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What physical parameters define colors like the pigment primaries - red, blue and yellow - and their mixtures? How about light primaries?
 
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What do you mean by physical parameters? The wavelength of light determines its colour, but I guess you already knew that. As for pigments, if you mean, what property of a substance determines its colour, then I guess that has to do with atomic structure or is quantum mechanical. Primary pigments absorb one of the primary colours (wavelengths) and reflect the others.
 
My question is basically: what frequencies are assigned to which primary colors, and what is the mechanism that would describe secondary colors as primary combinations corresponding to single frequencies?
 
Just look up the EM wavelength chart. Different colors are at different wavelengths.
 
That chart is more qualitative than physical regarding a precise definition for primary and secondary colors. Please refer to my previous post. E. g., what is the exact frequency or range of frequencies for the color blue, and how is green defined as a mixture of yellow and blue frequencies?
 
You perceive Yellow & Blue as green but it's not really green. Its all about how your eye and brain perceives colors, your eye can't distinguish between real green light and the mixture of yellow and blue. A very interesting question you can ask is if you have a yellow and blue dot separated by a distance x , how far away do you have to be to see green? For the color/wavelengths I will again refer you to a EM chart, it's out there.
 
my question is, can anyone?
when you see blue and green light,
don't the wavelenghts add up to green anyways?
wave-wise
 
No, it's biology of the eye. It's all about the cones and rods, but mostly cones for color.
 
so wavelength-wise two waves, a blue and a yellow, arent the same as one, a green?
they look the same but they are not?
im confused
 
  • #10
I'll refer you too any of the good references on color vision. You're getting into more biology.
 
  • #11
Maybe, in part, colors are defined by the blackbody spectrum of the sun.
 
  • #12
No, color is not defined by blackbody radiation.
 
  • #13
The answer lies primarily in the phototransduction mechanism in the eye, but there's a rough connection with averaging wavelengths as well. I'm certainly not qualified to discourse on this with any authority, but from my scant understanding...

...the crude version of the mechanism involves photoexcitation in the retina. Each such event creates a mobile electron-ion pair of related energy, which affect the membrane potential of the photoreceptor. This potential is what gets coded as a color.
 
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