why light is consist of seven or more color not only three color?

[PEOPLE]

Newton divided the spectrum into seven named colors: red, orange, yellow, green, blue, indigo, and violet, but I think it is not correct. I think light is only consist of three colors, red , green and blue and it is not consist of seven color or more. The reason is when light dispersed by prism, there are overlap by red, green and blue.

If light only have one kind of color light, and it through a prism, the result should be below.

 

 

If light is consist of two kind of color light.

 

 

If light is consist of three kind of color light.

 

 

We know that when three primary color combine, they can form other color.
when red combine with green, it become yellow and when green combine with blue it become cyan.
So the result should like that.

 

 

We can see that the picture of "If light consist of three kind of color" is very similar to goethe observation in goethe color theory and some light through a prism photo.

 

 

 

So I think the color we see after light through a prism, yellow is the combination of red and green,
cyan is the combination of green and blue.

Otherwise, there a photo about sunlight through a prism, and it seem like three color overlap together.

 

 

We can see it seem like three circle overlap together.

There also a little experiment about prism. It only need to prepare a piece of black paper and white and coloured paper strips, to get a better result, it should be better to prepare triangle like shape paper to do this experiment. (1)
Put a triangle like shape of white paper on a dark surface and look at it through a prism. You can see it seem like three triangle overlap together and this pattern seem like red light, green light and blue light overlap together.

There a result about using white lamp.

 

 

And this is the result using sunlight.

 

 

Reference:

1. http://www.itp.uni-hannover.de/~zawischa/ITP/prism.html

Photo:

http://www.gadgetscience.com/explanation-of-color-from-a-prism/

[Klaynos]

Research additive and subtractive colours.

 

We have more subtle ways to measure the wavelength of light and it can be shown that white light incandescent sources are a continuous spectrum of wavelength/frequency/energy.

There is of course the added complication that human eyes are not good measuring devices. They're nonlinear and only have 3 colour sensors, with overlapping frequency response.

[John Cuthber]

Newton chose 7 because it had some mystical significance to him and this went along with his religious beliefs.

 

however the light from a yellow LED or a sodium lamp is yellow. if you put it through a prism it stays yellow, rather than splitting into red and green.

The images produced on a computer monitor may be misleading because it only uses 3 colours (GRB) to represent all the colours.

 

the eye can distinguish a lot more than 7 colours and modern spectrometry can split the visible spectrum into millions of different wavelengths.

[PEOPLE]

Newton chose 7 because it had some mystical significance to him and this went along with his religious beliefs.

 

however the light from a yellow LED or a sodium lamp is yellow. if you put it through a prism it stays yellow, rather than splitting into red and green.

The images produced on a computer monitor may be misleading because it only uses 3 colours (GRB) to represent all the colours.

 

the eye can distinguish a lot more than 7 colours and modern spectrometry can split the visible spectrum into millions of different wavelengths.

 

A yellow LED or a sodium lamp light through a prism do not splitting into red and green can prove the monochromatic yellow light exist

but it can not prove the sunlight consist of monochromatic yellow light. As the yellow is clearly only appear in the intersection of red light and green light after sunlight through a prism,

so it has high possibility that monochromatic yellow light do not exist in sunlight, it's worth to do a experiment to see is the yellow light in sunlight really can not splitting into red and green.

[Klaynos]

The prism splitting of light isn't heat pretty but the dispersion fits a mathematical model. This is also true for sunlight on diffraction gratings where the grating equation is found to be true.

 

To have any hope of a counter argument you would need an equally (or more) accurate mathematical model to explain the observations. Do you have such a model?

[John Cuthber]

 

 

A yellow LED or a sodium lamp light through a prism do not splitting into red and green can prove the monochromatic yellow light exist

but it can not prove the sunlight consist of monochromatic yellow light. As the yellow is clearly only appear in the intersection of red light and green light after sunlight through a prism,

so it has high possibility that monochromatic yellow light do not exist in sunlight, it's worth to do a experiment to see is the yellow light in sunlight really can not splitting into red and green.

 

Actually, you can.

Let a beam of sunlight pass through a prism and split into a spectrum.

than place a piece of black paper with a slit cut in it in the spectrum so the slit only lets the yellow light through.

Then pass that yellow light through another prism.

It stays yellow and un-split (assuming you set this up properly).

This experiment has been done countless times.

There's light in sunlight that is genuinely yellow.

[Enteroctopus]

This disregards the remainder of the spectrum. Why did Newton choose seven? He could see them, so he had some reasonably accurate means for showing that the observed colors were there, and others could repeat this in the affirmative.

 

We can detect infrared, UVA, UVB and so on with modern sensors. They are not discreet "colors" but a continuous spectrum, although there are distinct peaks derived from the absorption and emission spectra of gasses, and so one can easily show that the sun or an incandescent bulb or a candle's flame have strong and distinct coloration. Of course they do! They have gasses absorbing and emitting light which account for the observation.

 

Red and blue shift is further evidence of the continuity of the light spectrum because the distinct lines "move" depending upon the relative motion of the source.

Edited April 22, 2015 by Enteroctopus

[swansont]

This disregards the remainder of the spectrum. Why did Newton choose seven?

To make the colors match up with the major scale in music.

http://en.wikipedia.org/wiki/Roy_G._Biv

 

IOW, it was an artificial constraint he placed on the problem.

[PEOPLE]

Actually, you can.

Let a beam of sunlight pass through a prism and split into a spectrum.

than place a piece of black paper with a slit cut in it in the spectrum so the slit only lets the yellow light through.

Then pass that yellow light through another prism.

It stays yellow and un-split (assuming you set this up properly).

This experiment has been done countless times.

There's light in sunlight that is genuinely yellow.

 

I found someone do this experiment, but fail to get the unchangeable colour after yellow light through a second prism.

 

https://www1.umn.edu/ships/updates/newton1.htm

 

Much later, in the 1720s (after Newton's 1704 Opticks), Giovanni Rizzetti, in Venice, specificed his own conditions for what constituted a good experiment with two prisms:

care is to be taken that the second prism is not too distant from the first, nor the slit, through which the light of one colour is transmitted from refraction at the first prism to the second, is too narrow.

These, of course, were exactly the opposite of Newton's criteria. And the conclusions that Rizzetti reached were likewise quite different. For him, pure yellow light transformed itself, upon a second refraction, into red, green and indigo--with the yellow itself disappearing.

https://books.google.com.hk/books?id=Bk4sUpSx1LsC&printsec=frontcover&hl=zh-TW#v=onepage&q&f=false

page 98

The English claimed that Rizzetti, having made use of Prisms made at Venice, which are not of so pure a Cristall as ours, has been led into

the many mistakes he has asserted for convincing proofs.

The result is denied because the prism is made at Venice.

page 99

Algarotti reported that when he had tried the experimentum crucis he had failed to produce unchangeable colours,

because our Prisms in Italy are of no other use than to amuse Children or hang up as a fine shew in some window in

the country'. In contrast, the 'crucial' experiment worked well with prisms sent from England;'these we esteemed as sacred.

Not only one people can not see the unchangeble colour when do this experiment.

I also found someone do this experiment, and below is the result when yellow, green and light blue through the second prism.

http://southerncrossreview.org/74/tao-colors-2.html

The yellow light through second prism result is similar to Rizzetti's result, it splitting into red, green and blue with yellow itself disappearing.

[Klaynos]

Monochromatic light will not split. I've conducted that experiment countless times.

 

You've completely ignored my last post.

[StringJunky]

This physics lesson is a nice potted treatise on the history, physics and perception of colour. The author seems to think there is only six visible rainbow colours:

 

"Indigo. The only time I ever hear it is when students recite the visible spectrum. Indigo is a color of relatively little importance. If indigo counts as a color then so should canary, and mauve, and puce, and brick, and teal, and so on. Where is their place in the spectrum?"

Edited April 24, 2015 by StringJunky

[PEOPLE]

Monochromatic light will not split. I've conducted that experiment countless times.

 

You've completely ignored my last post.

 

There are so many people do Newton's Experimentum Crucis is failed in the history.

 

https://books.google.com.hk/books?id=lwcDZ0Ex4lYC&printsec=frontcover&hl=zh-TW#v=onepage&q&f=false

 

Page 43

 

Sir Robert Moray, who served as the first president of the Royal Society, proposed four simplistic and

essentially worthless experiments as a means of verifying the experimentum crucis, which Moray lacked the skill to

duplicate himself. Then from France came a long letter written by Ignance Gaston Pardies, a professor of speech and a

member of the Society of Jesus, a learned order of Roman Catholic priests. Like Moray, Pardies had failed in several

attempts to duplicate the expermentum crucis and concluded that Newton's results lacked scientific merit.

Can you show any prove to prove yellow light in sunlight will not split by newton's expermentum crucis?

[John Cuthber]

There's a fundamental problem with the way that Newton used prisms.

Unless you use other bits of equipment (lenses and slits) you get overlapping images.

If you take the trouble to eliminate those overlaps then you get yellow light that's genuinely yellow from the sun.

It won't be split into red and green by a prism.

[StringJunky]

...It won't be split into red and green by a prism.

Then what is the yellow that red and green produce?. Is it because the blue component in green cancels the red component leaving yellow? Also, why are the three primary light colours in monitors and the cones in our eyes RGB and not RYB?

[swansont]

Then what is the yellow that red and green produce?. Is it because the blue component in green cancels the red component leaving yellow? Also, why are the three primary light colours in monitors and the cones in our eyes RGB and not RYB?

That's because of the way the eye works, having three color receptors.

[PEOPLE]

1984 New Scientist

 

https://books.google.com.hk/books?id=QBZ2WG0HdEQC&&pg=PA45&lpg=PA45&printsec=frontcover&hl=zh-TW#v=onepage&q&f=false

 

page 45

 

Newton's case is interesting because John Lucas, a comtemporary, tried and failed to reproduce the Experimentum crucis.

As explained in the Box, this resulted from Newton's prismatic light not being monochromatic.

Furthermore, from his reply to Lucas, we know that Newton was fully aware of this.

His 1671 account of Experimentum crucis in the Philosophical Transaction of the Royal Society is clearly

an idealisation of what should have happened given Newton's claims of light. We know that Newton's

idealisations were correct; the colour of monochromatic light is not altered by passage through prisms.

An interesting question is how he arrived at this conclusion. Despite the wording of the 1671 paper,

it seems unlikely that the Experimentum crucis counld have led to this conclusion; the Experimentum crucis

appears more likely to be a justification of his hypothesis than a route to discovery.

It seems Experimentum crucis can not prove yellow light in sunlight is monochromatic light.

[StringJunky]

That's because of the way the eye works, having three color receptors.

Are monitors/TVs RGB because our eyes are?

[Klaynos]

Are monitors/TVs RGB because our eyes are?

Yep. The technology was developed to allow a wide range of colour perception to humans.

 

 

There are so many people do Newton's Experimentum Crucis is failed in the history.

 

https://books.google.com.hk/books?id=lwcDZ0Ex4lYC&printsec=frontcover&hl=zh-TW#v=onepage&q&f=false

 

Page 43

 

Sir Robert Moray, who served as the first president of the Royal Society, proposed four simplistic and

essentially worthless experiments as a means of verifying the experimentum crucis, which Moray lacked the skill to

duplicate himself. Then from France came a long letter written by Ignance Gaston Pardies, a professor of speech and a

member of the Society of Jesus, a learned order of Roman Catholic priests. Like Moray, Pardies had failed in several

attempts to duplicate the expermentum crucis and concluded that Newton's results lacked scientific merit.

 

Can you show any prove to prove yellow light in sunlight will not split by newton's expermentum crucis?

My point is that we have other experiments other then prisms which work better and are easier to understand in terms of wavelength. You can even remove the overlapping bands that John talks about, the maths shows you where the bands exist and where they come from.

[StringJunky]

Yep. The technology was developed to allow a wide range of colour perception to humans.

Cheers. What do I look for on Google to find the mathematical parameters/relationships of colours - frequency and/or wavelength - and how they add or cancel to make another colour?

[Klaynos]

RGB colour space.

 

Physiology of colour perception.

[PEOPLE]

Sunlight is consist of seven or more color light in current theory, as three primary light also can get the same result about sunlight through a prism. So the result of diffraction gratings

about three primary color light source and seven or more color light source also is the same.

If there are one light source has only three primary color and another light source has seven or more color. How do diffraction gratings distinguish which light source has

only three color?

And there are some photo about white light dispersed by Diffraction Grating.

when white light dispersed by Diffraction Grating, yellow light and cyan light is disappear slowly, and it seems like three color at last.

Is current theory no need to explain any strange phenomenon?

Why sunlight through the prism seem like three color overlap but it is actually consist of seven or more color?

[Klaynos]

A diffraction grating would show gaps if the source was made of three colours, is out was not 3 it would show a continuous spectrum. Sunlight and incandescent light bulbs produce a continuous spectrum with energies consistent with our understanding.

 

The current theory explains it, second order dispersion as explained above.

 

The seven colours is a historical artifact, it's a continuous spectrum.

[IAstroViz]

With all the info I have seen you seem to have a point. But Newton's theory seems to be more thoughtworthy.

[Klaynos]

With all the info I have seen you seem to have a point. But Newton's theory seems to be more thoughtworthy.

He really doesn't. Our understanding of light has moved on a lot side newton.