# Color vision

#### StatusX

Homework Helper
I'm not sure if this is the right forum for it, but I had a few questions about how color vision works. I know that mixtures of pure colors look like other pure colors. For example, some mixture of pure (monochromatic) green and blue looks like pure yellow. So for a given color, are there an infinite number of different mixtures of colors that look the same? How would you go about finding the frequency of a color that a given mixture of colors corresponds to? And how about converting a frequency to an RGB value?

Related Biology and Medical News on Phys.org

#### neurocomp2003

are you asking how the visual system responds to different colour frequencies or how
these colours are made up in teh physics sense?

#### StatusX

Homework Helper
I'm saying, given a certain mixture of photons of different wavelengths that are hitting your eye (eg, 30% at 500nm, 45% at 600nm, and 25% at 700nm), what is the wavelength of monochromatic light that would look the same? Or is there not always one? And how do you convert wavelength to RGB values?

#### neurocomp2003

again: so your asking how does the visual system interprets light then? because converting from light to RGB values is a cathode rays thing)

#### StatusX

Homework Helper
I don't see what your confusion is. For example, if I wanted to see 500 nm light on my computer screen, what would I set as RGB values in, say, MS Paint.

#### neurocomp2003

my confusion is are you asking the Neuropsychology Method OR the mechanical Method

What the actual Eye sees and how MSPaint/CRTs make color are different.

#### StatusX

Homework Helper
I just want to know how mixtures of light look to the human eye. I don't understand how else you could take my original question. For example, you might say something like:

Light made of 75% 500 nm and 25% 600nm, according to this formula ....... would look the same as 518nm light.

#### neurocomp2003

Because the visual system may not be as simple as "formula" as 500nm = 501nm...the visual system is more complicated then CRT tubes...go pick up a standard neuropsychology book look up the section on teh visual system: see how the cones detect color(3 types) then proceed to V1 to V3 OR V4...look up the concepts of Constancy & Intensity.

### Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving