Light: visible or invisible?

[Furyan5]

33 minutes ago, koti said:

The only truth that comes from your post is the fact that you’ve been on this forum for about 4 months and you still haven’t mastered the subtle art of quoting someone. Oh, and nobody is saying that the eyes interpret anything. 

 

Lol really? BeeCee says exactly that. Scroll up a bit. 

Btw, I never claimed colors are the product of a single wavelength. I claimed that light itself has no color. 

1 minute ago, studiot said:

If you can only respond to one point at a time why do you post multiple points in your posts.?

one question.

I'm sorry I can't respond to your second point (as requested) in your last post until we finish this one.

I can only respond to one. You can respond to many. 

[beecee]

1 hour ago, Furyan5 said:

Wrong. Our eyes detect 630nm wavelength light and send electrochemical impulses to our brains visual cortex where our brain creates the sensation orange. Our eyes see nothing. They detect, they don't perceive. 

Our eyes detect/see all of the EMS from 400nm to 700nm, and the actual specific wavelength is interpreted/seen  as a colour when the impulses are sent to the brain. Anything else is unecessary philosophical pedant.

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If 630nm light was orange, we would see it being reflected by the Orange in all directions.

So? An Orange under normal lighting conditions on earth, appears/is seen as orange, again, so?

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I know it's hard to let go of a preconception. It blinds you to the truth.

Yes, you need to let go. As I said before, "I believe the belief that an Orange is orange in any condition of lighting or lack thereof, is an example of what I call "intuitiveness bias" Obviously we all know under normal conditions on planet Earth, under normal light, an Orange is orange....no question about it. But altering those normal lighting conditions, or removing the lighting, and it is easily seen I believe, that the colour or lack thereof of any object depends in the first instance on that precise EMS or lack of" 

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The eye serves just one purpose. It converts light into an electrochemical signal. It doesn't interpret anything. It doesn't perceive anything. 

And that is perceived/seen/interpreted as light of a specific colour...Unless of course there is no light and then we have blackness or no colour.

 

 

Quote

http://www.dailymail.co.uk/sciencetech/article-3093457/Does-colour-exist-BRAIN-Book-argues-simply-construct-mind.html

Giving some link from a tabloid newspaper such as the "Daily Mail" MEANS sfa on a science forum.

Edited March 11, 2018 by beecee

[studiot]

5 minutes ago, Furyan5 said:

I can only respond to one. You can respond to many. 

Magnanimous of you.

How is that supposed to work?

[Rob McEachern]

"Consider an experience I had recently. A book with a red cover had been left on top of the dashboard of my car in such a way that I could see a red reflection of the book as I looked through the windshield. I was surprised to find that distant objects retained their normal colors as they were viewed through the red reflection. Even green objects seen through the red reflection looked green. This interested me because I of course knew that when red and green light are mixed in isolation, they form yellow. Then when I held up my hand to block the rest of the scene and viewed just the patch of the red and green through a small opening between my fingers, I did see yellow."

from Alan L. Gilchrist, "The Perception of Surface Blacks and Whites", Scientific American, March 1979.

[studiot]

1 minute ago, beecee said:

Our eyes detect/see all of the EMS from 400nm to 700nm, and the actual specific wavelength is interpreted/seen  as a colour when the impulses are sent to the brain. Anything else is unecessary philosophical pedant.

 

Yes our eyes detect, but furyan5's link is right that colour is a mixture of many wavelengths.

Further the link explains how the detectors don't detect wavelengths as single wavelength, but as part of a range.

The part of the EMS you mention is split into three for this purpose in most people.

[beecee]

8 minutes ago, Furyan5 said:

Lol really? BeeCee says exactly that. Scroll up a bit. 

beecee says our eyes detect/interpret/see light and the exact nature of that light is interpreted as a specific colour. Again, if we have no EMS, we have no colour or black.

Quote

Btw, I never claimed colors are the product of a single wavelength. I claimed that light itself has no color. 

Your claims so far seem rather philosophical and rampant, rather then observational physics.

 

[Furyan5]

15 minutes ago, studiot said:

Magnanimous of you.

How is that supposed to work?

You ask, and I answer. 

I'm talking to three people. Only one comment is directed at you.

[beecee]

http://www.physicsclassroom.com/class/light/Lesson-2/Visible-Light-and-the-Eye-s-Response

Visible Light Spectrum

The focus of Lesson 2 will be upon the visible light region - the very narrow band of wavelengths located to the right of the infrared region and to the left of the ultraviolet region. Though electromagnetic waves exist in a vast range of wavelengths, our eyes are sensitive to only a very narrow band. Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum. Normally when we use the term "light," we are referring to a type of electromagnetic wave that stimulates the retina of our eyes. In this sense, we are referring to visible light, a small spectrum from the enormous range of frequencies of electromagnetic radiation. This visible light region consists of a spectrum of wavelengths that range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm. Expressed in more familiar units, the range of wavelengths extends from 7 x 10^-7 meter to 4 x 10^-7 meter. This narrow band of visible light is affectionately known as ROYGBIV.

As mentioned in the first section of Lesson 2, our eyes are sensitive to a very narrow band of frequencies within the enormous range of frequencies of the electromagnetic spectrum. This narrow band of frequencies is referred to as the visible light spectrum. Visible light - that which is detectable by the human eye - consists of wavelengths ranging from approximately 780 nanometer (7.80 x 10^-7 m) down to 390 nanometer (3.90 x 10^-7 m). Specific wavelengths within the spectrum correspond to a specific color based upon how humans typically perceive light of that wavelength. The long wavelength end of the spectrum corresponds to light that is perceived by humans to be red and the short wavelength end of the spectrum corresponds to light that is perceived to be violet. Other colors within the spectrum include orange, yellow, green and blue. The graphic below depicts the approximate range of wavelengths that are associated with the various perceived colors within the spectrum.

[Furyan5]

11 minutes ago, beecee said:

beecee says our eyes detect/interpret/see light and the exact nature of that light is interpreted as a specific colour. Again, if we have no EMS, we have no colour or black.

Your claims so far seem rather philosophical and rampant, rather then observational physics.

 

Would a quote from Isaac Newton himself convince you? Optiks 1701. "For the waves themselves are not coloured."

2 minutes ago, beecee said:

http://www.physicsclassroom.com/class/light/Lesson-2/Visible-Light-and-the-Eye-s-Response

Visible Light Spectrum

The focus of Lesson 2 will be upon the visible light region - the very narrow band of wavelengths located to the right of the infrared region and to the left of the ultraviolet region. Though electromagnetic waves exist in a vast range of wavelengths, our eyes are sensitive to only a very narrow band. Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum. Normally when we use the term "light," we are referring to a type of electromagnetic wave that stimulates the retina of our eyes. In this sense, we are referring to visible light, a small spectrum from the enormous range of frequencies of electromagnetic radiation. This visible light region consists of a spectrum of wavelengths that range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm. Expressed in more familiar units, the range of wavelengths extends from 7 x 10^-7 meter to 4 x 10^-7 meter. This narrow band of visible light is affectionately known as ROYGBIV.

As mentioned in the first section of Lesson 2, our eyes are sensitive to a very narrow band of frequencies within the enormous range of frequencies of the electromagnetic spectrum. This narrow band of frequencies is referred to as the visible light spectrum. Visible light - that which is detectable by the human eye - consists of wavelengths ranging from approximately 780 nanometer (7.80 x 10^-7 m) down to 390 nanometer (3.90 x 10^-7 m). Specific wavelengths within the spectrum correspond to a specific color based upon how humans typically perceive light of that wavelength. The long wavelength end of the spectrum corresponds to light that is perceived by humans to be red and the short wavelength end of the spectrum corresponds to light that is perceived to be violet. Other colors within the spectrum include orange, yellow, green and blue. The graphic below depicts the approximate range of wavelengths that are associated with the various perceived colors within the spectrum.

Thank you. Read carefully. It says "Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum". It's not the light we see. It's the light which allows us to see. 

need more?

[studiot]

21 minutes ago, Rob McEachern said:

"Consider an experience I had recently. A book with a red cover had been left on top of the dashboard of my car in such a way that I could see a red reflection of the book as I looked through the windshield. I was surprised to find that distant objects retained their normal colors as they were viewed through the red reflection. Even green objects seen through the red reflection looked green. This interested me because I of course knew that when red and green light are mixed in isolation, they form yellow. Then when I held up my hand to block the rest of the scene and viewed just the patch of the red and green through a small opening between my fingers, I did see yellow."

from Alan L. Gilchrist, "The Perception of Surface Blacks and Whites", Scientific American, March 1979.

 

I would suggest that the reason for your experience is that the strength of the reflected red light is actually quite small compared to the strength of the light coming through the window so this dominates/overrides the red in bulk.

But when you cut the receiving area down that balance changes in favour of the red.

 

Please note this is entirely consistent with furyan5's link, which I will repeat here as it offers an simple explanation of the mixing of colours.

 

https://kids.frontiersin.org/article/10.3389/frym.2013.00010

[Rob McEachern]

9 minutes ago, beecee said:

Specific wavelengths within the spectrum correspond to a specific color

However, the converse is not true. A specific color can be produced by combinations of several wavelengths, as when red and green combine to form yellow.

[Furyan5]

3 minutes ago, Rob McEachern said:

However, the converse is not true. A specific color can be produced by combinations of several wavelengths, as when red and green combine to form yellow.

And, there is no pink wavelength 

[Rob McEachern]

3 minutes ago, studiot said:

I would suggest that the reason for your experience is that the strength of the reflected red light is actually quite small compared to the strength of the light coming through the window so this dominates/overrides the red in bulk.

It was not my experience - I was quoting from an article in Scientific American. The red and green must be of approximately equal intensity, in order for their combination to produce yellow.

[beecee]

9 minutes ago, Furyan5 said:

Thank you. Read carefully. It says "Since this narrow band of wavelengths is the means by which humans see, we refer to it as the visible light spectrum". It's not the light we see. It's the light which allows us to see. 

Wow!! Are you trying to be funny? Talk  about philosophical pedantic nonsense!

Let me sum it up for you...We see light, which we call the EMS. Black is the absence of light/colour, or a property of the object absorbing all of the EMS.

And while in a technical sense, it is really not appropriate to refer to light as being colored. Light is simply a wave with a specific wavelength or a mixture of wavelengths; it has no color in and of itself. An object that is emitting or reflecting light to our eye appears to have a specific color as the result of the eye-brain response to the wavelength. 

http://www.physicsclassroom.com/class/light/Lesson-2/Visible-Light-and-the-Eye-s-Response

6 minutes ago, Rob McEachern said:

However, the converse is not true. A specific color can be produced by combinations of several wavelengths, as when red and green combine to form yellow.

Agreed.

[studiot]

1 minute ago, Rob McEachern said:

However, the converse is not true. A specific color can be produced by combinations of several wavelengths, as when red and green combine to form yellow.

True but incomplete.

Please not my comments a few posts back about the actual sensors splitting the incoming light into 3 bands.

[Rob McEachern]

4 minutes ago, Furyan5 said:

And, there is no pink wavelength

Or brown, or purple, or magenta or cyan...

[studiot]

9 minutes ago, Rob McEachern said:

It was not my experience - I was quoting from an article in Scientific American. The red and green must be of approximately equal intensity, in order for their combination to produce yellow.

Thank you for that clarification, did you not want to discuss the mechanism of the effect you posted about, whoever saw it?

I thought it was an interesting contribution.

Edited March 12, 2018 by studiot

[Furyan5]

6 minutes ago, beecee said:

Wow!! Are you trying to be funny? Talk  about philosophical pedantic nonsense!

Let me sum it up for you...We see light, which we call the EMS. Black is the absence of light/colour, or a property of the object absorbing all of the EMS.

And while in a technical sense, it is really not appropriate to refer to light as being colored. Light is simply a wave with a specific wavelength or a mixture of wavelengths; it has no color in and of itself. An object that is emitting or reflecting light to our eye appears to have a specific color as the result of the eye-brain response to the wavelength. 

http://www.physicsclassroom.com/class/light/Lesson-2/Visible-Light-and-the-Eye-s-Response

Agreed.

That's your opinion. Nothing more, nothing less. 

[Rob McEachern]

5 minutes ago, studiot said:

the actual sensors splitting the incoming light into 3 bands

In normal humans. Many other creatures have different numbers. Mantis shrimp have 16.

[Furyan5]

Just now, Rob McEachern said:

In normal humans. Many other creatures have different numbers. Mantis shrimp have 16.

Many is shrimps lack the mental capacity to perceive as many colors as humans. They actually see no better than dogs.

[StringJunky]

5 hours ago, beecee said:

Orange is a result of the reflective properties of the object....

 

Or: Orange is a result of the reflective selective properties of the object

[Furyan5]

1 minute ago, StringJunky said:

Or: Orange is a result of the reflective selective properties of the object

Or, orange is a visual sensation created by our brain 

[StringJunky]

1 minute ago, Furyan5 said:

Or, orange is a visual sensation created by our brain 

Yes, but the object pre-filters what comes first and then the eye-brain does what it does with that.

[studiot]

7 minutes ago, StringJunky said:

Or: Orange is a result of the reflective selective properties of the object

Yea, +1

Good to point out there are more than one interpretation of many phenomena.

Edited March 12, 2018 by studiot

[Furyan5]

Just now, StringJunky said:

Yes, but the object pre-filters what comes first and then the eye-brain does what it does with that.

Correct. Technically, color is the property of the object, which causes it to absorb or reflect certain wavelengths of light. What we call colors, like red, yellow and green, are actually hues. So objects have colors and we perceive hues.