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originally posted by: Soylent Green Is People
Here's a pretty mundane question about the EM spectrum.

The colors of visible light spectrum are in the order as follows:

Red - Orange - Yellow - Green - Blue - Indigo - Violet

On the other side of red is "infrared", and on the other side of violet is "ultraviolet".

I understand that the color "orange" on the the spectrum is a cross between red and yellow -- i.e., as visible light morphs from red into yellow, it goes through a stage where it looks orange -- more yellow than red, but more red than yellow. Hence, orange is between red and yellow.

Similarly, green is a cross between yellow and blue. As visible light morphs from looking yellow to looking blue, it passes through a state of looking "green", which is sort of yellow and sort of blue. Hence it is between yellow and blue in the spectrum.

Most school children would say that "violet" is a cross between red and blue. However, I think violet can NOT be a cross between red and blue, because red and blue are on opposite opposite ends of the visible light spectrum.

So is it safe to assume that there is no red in the color violet? Because if violet really is a cross between red and blue, where does the red come from if it is on the opposite side of the visible light spectrum?

Color Wavelength
Violet 400 - 420 nm
Indigo 420 - 440 nm
Blue 440 - 490 nm
Green 490 - 570 nm
Yellow 570 - 585 nm
Orange 585 - 620 nm
Red 620 - 780 nm

this has nothing to do with mixing paint

what you see as objects colour is the reflected/emitted EM frequency

So is it safe to assume that there is no red in the color violet?

NO ! Violet is shorter wave than red
you can say, there is more violet in red but no red in violet

What is the most likely source of untapped energy?

originally posted by: BlueMule
What is the most likely source of untapped energy?

More efficient types of solar cells offer promise, and there are labs researching this topic.

gigaom.com...

The MIT researchers say that with these types of designs, which use heat to boost efficiency, some solar cells in theory could one day produce an efficiency of over 80 percent. In comparison some of the highest efficient solar cells in mass production currently are in the low 20 percent range from SunPower.

80 percent efficiency would be a big step up from 20 percent.

originally posted by: KrzYma

Color Wavelength
Violet 400 - 420 nm
Indigo 420 - 440 nm
Blue 440 - 490 nm
Green 490 - 570 nm
Yellow 570 - 585 nm
Orange 585 - 620 nm
Red 620 - 780 nm

this has nothing to do with mixing paint

what you see as objects colour is the reflected/emitted EM frequency

So is it safe to assume that there is no red in the color violet?

NO ! Violet is shorter wave than red
you can say, there is more violet in red but no red in violet

Right. As I said already, I understand mixing light is not the same as mixing paint.

However, "orange" is a wavelength midway between red and yellow, and (not surprisingly) orange looks like a yellow-red color.

Similarly, "green" is a wavelength midway between yellow and blue, and (not surprisingly) green looks like a yellow-blue color.

To my eye (and most people's eyes) "violet" looks like a red-blue color, so applying the same logic as above, we would expect violet to be a wavelength midway between blue and red...

...but it isn't. That just seemed counter-intuitive to me.

a reply to: Arbitrageur

That would indeed be great, but it is still going from tapped to tapped so it doesn't answer my question.

originally posted by: KrzYma


this has nothing to do with mixing paint

what you see as objects colour is the reflected/emitted EM frequency

So is it safe to assume that there is no red in the color violet?

NO ! Violet is shorter wave than red
you can say, there is more violet in red but no red in violet

Bold mine. This is right.

I dont know "science" , but I know art, and I know colour theory. Subtractive (light/RGB), Additive (paint/ink/CMYK). opposite, one emits, the other reflects. This may sound as sensible as random nylon threads, but... this is ATS.

a reply to: KrzYma

NO ! Violet is shorter wave than red you can say, there is more violet in red but no red in violet

He was talking about the color violet, since red is a primary color there must be red in the color violet.

a reply to: KrzYma

this has nothing to do with mixing paint what you see as objects colour is the reflected/emitted EM frequency

So how do you make violet paint, and does violet paint not reflect a combination of red and blue wavelengths?

originally posted by: BlueMule
a reply to: Arbitrageur

That would indeed be great, but it is still going from tapped to tapped so it doesn't answer my question.

I see it differently. If you go from 20% tapped to 80% tapped, you have now tapped 60% that wasn't tapped before.

But that is not an accurate assessment of the impact of such a technology advancement.

In reality what happens is many solar installations are simply never done because the return on investment at 20% efficiency is insufficient to justify the investment.

If the efficiency is 80%, in many of these cases, the return on investment will justify the investment. So in those cases, which I believe to far outnumber current installations, you could go from completely untapped, to tapped. It would literally transform the energy market.

a reply to: BlueMule

What is the most likely source of untapped energy?

If we can get a fusion reactor working efficiently it will one of the greatest achievements of mankind. We will be able to power the world on nothing more than water.

originally posted by: PhoenixOD
If we can get a fusion reactor working efficiently it will one of the greatest achievements of mankind. We will be able to power the world on nothing more than water.

And my point was, we already have one, we just aren't making much use of it, it's mostly untapped energy:

Solar Energy

The amount of solar energy reaching the surface of the planet is so vast that in one year it is about twice as much as will ever be obtained from all of the Earth's non-renewable resources of coal, oil, natural gas, and mined uranium combined

originally posted by: BlueMule
a reply to: Arbitrageur

That would indeed be great, but it is still going from tapped to tapped so it doesn't answer my question.

Well id say untapped would be fusion but for an even more exotic source of energy how anout gravity. Since we know gravitational waves exist much like we do using surf from the ocean we could use those gravtational waves to make energy but before you ask i dont know how that would work. I read it in a paper and it was entirely theoretical.

originally posted by: SuperVizorr
a reply to: KrzYma

this has nothing to do with mixing paint what you see as objects colour is the reflected/emitted EM frequency

So how do you make violet paint, and does violet paint not reflect a combination of red and blue wavelenghts?

yes it does, some pigments reflect red some pigments reflect blue

so 700 nm for red plus 465 for blue ( middle wavelength of each)

your brain can not separate those, like it can not separate all other mixture of wavelengths, it interprets it as violet.
all visible wavelengths together seem for us white

is there any wavelength for white ?
NO !

your brain plays tricks with you

a reply to: KrzYma

Right. But just like the wavelength of orange light is midway between the wavelengths of red and yellow, and the wavelength of green light is midway between the wavelengths of yellow and blue, I intuitively almost expect violet light to be midway between blue and red -- but it isn't.

Sure -- violet is as equidistant from blue as green is from yellow (comparing wavelengths), but it is not anywhere close to the wavelength for red.

So looking at the spectrum, violet light seems to have no relationship to red light -- not the same relationship that (say, for example) orange light has to red light.

a reply to: KrzYma

Yes I understand this, my point is that mixing paint and the wavelengths of light do have something to do with each other.

It is the notion that a certain mix color consists of light of a wavelengths directly in between the wavelengths of two adjacent primary colors, in the light spectrum, that is false, even though it is a logical mistake to make.

a reply to: Soylent Green Is People

To my eye (and most people's eyes) "violet" looks like a red-blue color, so applying the same logic as above, we would expect violet to be a wavelength midway between blue and red...

I think the range how we have build colour pallets, especially in digital numbers, has more to do with mathematics rather than real distribution of wave lengths in visible spectrum.
We use a close circle to digitally represent all the colours, it is a continuous spectrum.
Real EM waves begin with gamma rays and and with radio waves, they are linear

a reply to: Arbitrageur

And my point was, we already have one, we just aren't making much use of it

We have lots of countries working on it but we dont have a fully working self sustained fusion reactor yet as far as i know.

a reply to: BlueMule

Liquid fluoride thorium reactors are also a great way to make energy that we dont currently use. Thorium is much more abundant than uranium , not as dangerous and produces less toxic waste.

originally posted by: KrzYma
I think the range how we have build colour pallets, especially in digital numbers, has more to do with mathematics rather than real distribution of wave lengths in visible spectrum.
We use a close circle to digitally represent all the colours, it is a continuous spectrum.
Real EM waves begin with gamma rays and and with radio waves, they are linear

Yes. As I said in my post, if we look at a part of the EM spectrum that also includes visible light, we may see it go from:

-radar
-infrared
-the visible spectrum, starting with red and ending in violet
-ultraviolet
-X-rays

(with langer wavelengths of EM radiation before radar, and shorter wavelengths of EM radiation after x-rays).

So looking at the spectrum, violet light seems to have no relationship to red light -- at least not the same relationship that (say, for example) orange light has to red light. Because while orange and red are adjacent to each other on the spectrum, violet and red are not.

It just seems counter-intuitive (although it is true) that violet light does not have the same type of relationship to red light as orange does with red.

originally posted by: PhoenixOD
We have lots of countries working on it but we dont have a fully working self sustained fusion reactor yet as far as i know.

It's called the sun.