Why the sky is blue and not violet?

[DrDu]

Violet light stimulates both the red and blue receptors in the eye. So while spectral colours include pure blue and red, there is no spectral colour where red dominates over blue. The latter colour would be my definition of purple, which would be one of the few colours which do not occur as spectral colours.
There is plenty of space for experiments, e.g. comparing the spectral colour with some rgb colours on the screen.

 

[sophiecentaur]

Violet light stimulates both the red and blue receptors in the eye. So while spectral colours include pure blue and red, there is no spectral colour where red dominates over blue. The latter colour would be my definition of purple, which would be one of the few colours which do not occur as spectral colours.
There is plenty of space for experiments, e.g. comparing the spectral colour with some rgb colours on the screen.

Mostly Blue end receptor but also Middle and Red end receptors. This is not displays we're discussing. Red dominates over Blue in Spectral Red, btw.
Yes. Displays could be used but they cannot produce colours outside the phosphor gamut.

 

[mainliner]

I have some confusions about this that I'm not finding clear answers for. First, looking at the color violet, it looks like a sort of "purple". The answer as I've understood it to why the sky doesn't appear violet or this "purple" is that it has to do with a combination of the fact that there isn't as much violet produced by the sun and it's absorbed higher in the atmosphere. In addition to that is while violet appears sort of purple since it stimulates the blue cones and the red cones less, the net effect from the different frequencies of light coming into our eye is that the blue cones are stimulated most. So we see the sky as blue. What's confusing to me is that while thinking of violet as sort of a purple, I've come across some explanations that regard violet as a deep blue, not this "purplish" color. To add to this, if you look at a spectrum produced by a prism, it doesn't appear to show violet as this "purple" but a deep blue, however when you look at a rainbow you can see violet as this sort of purple. So I'm not sure what violet is actually perceived as. If violet is perceived as a purple, why doesn't this show up with a prism? If violet is perceived as a deep blue, why do we see "purple" where violet should be in a rainbow? Which is it?

this is a botanical question:)

its something to do with the blue hue hitting the atmosphere and dissipating over plant foliage during summer months, the sun is higher and the plants like blue light during vegetative stage, when the sun goes lower with the coming of autumn the atmosphere let's in more red when the flowers appear ... Its the magic of photosynthesis:)

im not a botanist put its something like this :)

indoor hydroponics growers use 7000k blue for veg and 2000k red for flower ... IM not sure what the mn is .

you've heard the saying " red sky at night Sheppard's delight" :)

that's all iv got hope this helps :)

 

[mainliner]

You already know this i presume:)

 

[DrDu]

Red dominates over Blue in Spectral Red, btw.
Yes.

Certainly, but in spectral red, green receptors will be stimulated even more than blue receptors, so you won't get the impression of purple.