question about colors mixing

[gib65]

If you took red light (700nm) and mixed it with green light (400nm), would the resulting light have a wavelength of about 550nm (which would be a yellowish orange) - or would it just be an overlap of red and green light, the only "yellow/orange" coming about after the physiological effects have produced the perception of it? Putting this another way, I'm asking if the mixing of colors is a phenomenon that happens only at the level of our physiology (i.e. the visual system) or does it happen in very physics of light?

[CaptainPanic]

There will merely be an overlap of the two types of light.

 

With a filter that blocks red light you would see only the green light.

 

The sunlight is a combination of light of a lot of different types of light with different wavelengths (the rainbow shows how many types ).

 

Not sure where the idea of the "orange light" is starting... but it seems probable that this is only in our heads.

[YT2095]

I believe it has something to do with beat frequency oscillations, a bit like playing a cord on a piano, you`ll get harmonics as a product of the 2 notes, that wouldn`t be there if each way played individually.

[swansont]

Beats will occur at the difference frequency (and sum frequency), but in EM radiation you only get that under certain conditions. When you add different colors of light, the average frequency or wavelength isn't present — that's all interpretation in the brain, as CaptainPanic has noted.

[Klaynos]

The brain doesn't always go for the average either... it's quite a complicated system iirc...

[gib65]

Thanks for the answers.

[Daecon]

So what if you had a red filter over yellow light?

[CaptainPanic]

If you have perfect (monochrome) yellow light, so 560 nm, and a filter for red light only (filtering only wavelengths from 600 nm to 700 nm), then the yellow light just passes through, as if there was no filter at all.

 

Note: if you take a colored piece of glass as a filter, this might filter more than just 1 color. Also, the light from your lightbulb contains a lot of wavelengths.

[swansont]

If you have perfect (monochrome) yellow light, so 560 nm, and a filter for red light only (filtering only wavelengths from 600 nm to 700 nm), then the yellow light just passes through, as if there was no filter at all.

 

That's if the filter rejects red light (a band-reject, or "notch" filter). If it passes only red light (a bandpass filter), you'd get nothing at all.

[YT2095]

Note: if you take a colored piece of glass as a filter

 

as mentioned above, This would constitute a bandpass filter.

 

 

Red goggles for Green laser work, green goggles for Red laser work etc....

or even clear polarised depending on wave orientation (tilt your head if you want to see it).