The true look of lights

[swansont]

19 hours ago, Hasan Özel said:

I miss,this was my fault,I am sorry for this. ☺️

Can we say like this,the yellow(500-730 nm)=red+green light is brighter than monochromatic yellow light (570-590 nm) ?

If we're talking about color perception, then light of the same intensity will appear brighter when you are closer to ~550 nm. That's where the eye is most sensitive. (in the early days of laser pointers, advertisements would sometimes claim their green laser pointer was as bright as a 5mW laser pointer. The green was 1 mW, but the eye is 5x more sensitive at that wavelength than the red)

So green + red could appear dimmer than pure yellow, simply because the eye is not as sensitive to the red  

[Hasan Özel]

3 hours ago, studiot said:

Hasan, it is good to have someone interested in the subject, especially as the last persion wanting to 'discuss' colour perception was a troll.

 

Thank you for your nice compliment Mr. Studiot 

I think the answer is correct which locates in Mehmet Saygın's comment.

3 hours ago, Mehmet Saygın said:

I think this is the answer of your question.

There is a difference between monochromatic yellow (570-590 nm) and yellow(500-730 nm),but not as you think.

Yellow = Green(500-570 nm) +Red (620-730 nm) light and monochromatic yellow(570-590 nm) is the same thing,because our eyes integrates Green+Red=Yellow and this combination of the light also a narrow range likes monochromatic yellow. But yellow(500-730 nm) is a different light,this light has a wider range and continuous spectrum. Both monochromatic yellow light and Yellow = Green(500-570 nm) +Red (620-730 nm) light has a lemonish yellow color. On the other hand, yellow(500-730 nm) has a creamy white color. This is the key. 

Your answer seems persuasive. I also wanted learn this difference. Thank you 

[studiot]

Did you read the Konica-Minolta document I linked to?

It really is an excellent presentation.

And it offers 'official' answers to your questions plus some that you haven't asked but need to.

 

[Hasan Özel]

3 hours ago, swansont said:

If we're talking about color perception, then light of the same intensity will appear brighter when you are closer to ~550 nm. That's where the eye is most sensitive. (in the early days of laser pointers, advertisements would sometimes claim their green laser pointer was as bright as a 5mW laser pointer. The green was 1 mW, but the eye is 5x more sensitive at that wavelength than the red)

So green + red could appear dimmer than pure yellow, simply because the eye is not as sensitive to the red  

I think this is the answer of your question.

There is a difference between monochromatic yellow (570-590 nm) and yellow(500-730 nm),but not as you think.

Yellow = Green(500-570 nm) +Red (620-730 nm) light and monochromatic yellow(570-590 nm) is the same thing,because our eyes integrates Green+Red=Yellow and this combination of the light also a narrow range likes monochromatic yellow. But yellow(500-730 nm) is a different light,this light has a wider range and continuous spectrum. Both monochromatic yellow light and Yellow = Green(500-570 nm) +Red (620-730 nm) light has a lemonish yellow color. On the other hand, yellow(500-730 nm) has a creamy white color. This is the key. 

I think this is the correct explanation. I also searched halogen lamb light and I saw the spectrum of these lights lie between 500-730 nm and has a continuous spectrum which is described as yellow light from me(wider range between green-red spectrum). The monochromatic yellow(570-590 nm) and yellow=green(500-570 nm)+red(620-730 nm) lights are the same thing. The halogen yellow light(500-730 nm) appearance is different from both monochromatic yellow(570-590 nm) and yellow=green(500-570 nm) +red(620-730 nm). Our eyes perceives yellow=green+red like a monochromatic yellow(570-590 nm). It means when we mix red+green for obtaining yellow light,the range these two lights do not confederate,only intersect,so these red+green light also have a narrow range like monochromatic yellow(570-590 nm). I can add a figure for comparison these 3 lights. 

 

50 minutes ago, studiot said:

Did you read the Konica-Minolta document I linked to?

It really is an excellent presentation.

And it offers 'official' answers to your questions plus some that you haven't asked but need to.

 

Yes I have reviewed, It occurs excellent information on color issues and colorimeter topic. 

Thank you for your special interest in this subject. 

Edited April 4, 2018 by Hasan Özel

[swansont]

3 minutes ago, Hasan Özel said:

I think this is the answer of your question.

There is a difference between monochromatic yellow (570-590 nm) and yellow(500-730 nm),but not as you think.

Yellow is not really 500-730 nm, and that wasn't the issue I was addressing.

 

[Hasan Özel]

6 minutes ago, swansont said:

Yellow is not really 500-730 nm, and that wasn't the issue I was addressing.

 

I also understood what do you mean, but the main idea is like that :

1) monochromatic yellow (570-590 nm) and yellow = red + green is the same thing, because the range of red (620-730 nm) and green (500-570 nm) intersect and make again a narrow band like monochromatic yellow, not wider like 500-730 nm. Because of this reason, monochromatic yellow and red+green is indistinguishable for eyes. The colors of these lights are between yellow-orange color.

2) If we have a light source which irradiates between 500-730 nm like halogen headlight, this light has a continuous spectrum. The color of this light is creamy yellow-white.

This is what I mean. 

 

[studiot]

1 hour ago, Hasan Özel said:

1) monochromatic yellow (570-590 nm) and yellow = red + green is the same thing, because the range of red (620-730 nm) and green (500-570 nm) intersect and make again a narrow band like monochromatic yellow, not wider like 500-730 nm. Because of this reason, monochromatic yellow and red+green is indistinguishable for eyes. The colors of these lights are between yellow-orange color.

 

I don't think so. (Issue underlined).

What do you think might be the physical mechanism for this to happen?

[swansont]

1 hour ago, Hasan Özel said:

I also understood what do you mean, but the main idea is like that :

1) monochromatic yellow (570-590 nm) and yellow = red + green is the same thing, because the range of red (620-730 nm) and green (500-570 nm) intersect and make again a narrow band like monochromatic yellow, not wider like 500-730 nm. Because of this reason, monochromatic yellow and red+green is indistinguishable for eyes. The colors of these lights are between yellow-orange color.

No. If you filter red + green with a true yellow filter, you will get little to no light.

Quote

2) If we have a light source which irradiates between 500-730 nm like halogen headlight, this light has a continuous spectrum. The color of this light is creamy yellow-white.

This is what I mean. 

 

But that's because you have a broad spectrum, dominated by yellow, rather than having just yellow light. Tungsten incandescent lights have a similar look. A yellowish cast, but emitting over the entire visible spectrum.

[Hasan Özel]

8 minutes ago, studiot said:

 

I don't think so. (Issue underlined).

What do you think might be the physical mechanism for this to happen?

As I underdstand it, we can illustrate this in the following way :

The monochromatic red light range is between 620-730 nm and the peak wavelength is 637 nm. The monochromatic green light range is between 500-570 nm and the peak wavelength is 523 nm. According to the picture I added. When the monochromatic green light range end, shortly after monochromatic red light range start. Let's remember the famous double-slit experiment which is owned by Thomas Young R.I.P and the part of his wave theory of light. The nodal points intersected by waves with two different wavelengths act like a new wave between the wave lengths of the two.

According to this idea, monochromatic yellow light(570-590 nm) and yellow=green(500-570)+red(620-730) looks like as a same light and yellow=green+red also has a narrow spectrum range like a monochromatic yellow light(570-590 nm).

 

[studiot]

I suggest you restudy the difference between additive and subtractive colour systems.

Since we have been dicussing the colour of light in this thread we are discussing the additive colour system, whereby you sart with no light (black) and add light of various colours, each time changing the result colour until you have added light of all colours when you get the white (or the near white broad spectrum (not necessarily continuous that is a different thing) of your halogen lamp.

This is how colour projectors work.

 

The alternative is the subtractive system where you start with white and remove particular colours either by filtering or by reflecting from a coloured object that removes the desired colour.
The end result of this is of course, no light or black.

This is how mixing paint colours works.

 

http://www.worqx.com/color/color_systems.htm

 

Edited April 4, 2018 by studiot

[Hasan Özel]

30 minutes ago, swansont said:

No. If you filter red + green with a true yellow filter, you will get little to no light.

I know the answer is no, but eye can not detects the difference. I mean if yellow=green+red light reflects the combination of these lights range between 500-730 nm, the monochromatic yellow (570-590 nm) and yellow = green (500-570 nm) + red (620-730 nm) light would not be indistinguishable for eye. So I said yellow=green+red also behaves like a monochromatic yellow light. This is the key 

30 minutes ago, swansont said:

But that's because you have a broad spectrum, dominated by yellow, rather than having just yellow light. Tungsten incandescent lights have a similar look. A yellowish cast, but emitting over the entire visible spectrum.

These lights irradiate between green-red part of visible spectrum (500-730 nm) and can not irradiate anything violet-blue part. Because of this reason, this kind of lights looks like us yellowish-white.

Edited April 4, 2018 by Hasan Özel

[swansont]

18 minutes ago, Hasan Özel said:

I know the answer is no, but eye can not detects the difference. I mean if yellow=green+red light reflects the combination of these lights range between 500-730 nm, the monochromatic yellow (570-590 nm) and yellow = green (500-570 nm) + red (620-730 nm) light would not be indistinguishable for eye. So I said yellow=green+red also behaves like a monochromatic yellow light. This is the key 

You implied that it would actually be monochromatic light. That was why objections were made.

[Hasan Özel]

36 minutes ago, swansont said:

You implied that it would actually be monochromatic light. That was why objections were made.

I want to say behaves like as a monochromatic light. I guess I have misrepresented myself 

1 hour ago, studiot said:

I suggest you restudy the difference between additive and subtractive colour systems.

Since we have been dicussing the colour of light in this thread we are discussing the additive colour system, whereby you sart with no light (black) and add light of various colours, each time changing the result colour until you have added light of all colours when you get the white (or the near white broad spectrum (not necessarily continuous that is a different thing) of your halogen lamp.

This is how colour projectors work.

 

The alternative is the subtractive system where you start with white and remove particular colours either by filtering or by reflecting from a coloured object that removes the desired colour.
The end result of this is of course, no light or black.

This is how mixing paint colours works.

 

http://www.worqx.com/color/color_systems.htm

 

I have read your reference link Mr. , but I try to explain this  :

If yellow=green+red light reflects the combination of these lights range between 500-730 nm (like a halogen lamb which has a creamy-white color light) , the monochromatic yellow (570-590 nm) and yellow = green (500-570 nm) + red (620-730 nm) light would not be indistinguishable for eye. So I said yellow=green+red also behaves like a monochromatic yellow light. This is the key 

Edited April 4, 2018 by Hasan Özel

[studiot]

48 minutes ago, Hasan Özel said:

 

I have read your reference link Mr. , but I try to explain this  :

If yellow=green+red light reflects the combination of these lights range between 500-730 nm (like a halogen lamb which has a creamy-white color light) , the monochromatic yellow (570-590 nm) and yellow = green (500-570 nm) + red (620-730 nm) light would not be indistinguishable for eye. So I said yellow=green+red also behaves like a monochromatic yellow light. This is the key 

But it doesn't, as I have tried to explain.

 

You are mixing up situations.

 

The way to see the colour of additive light sources is to shine them on a common area on a white screen or paper.
You don't stare into the beam.

 

What you then see in your two different situations looks different because it is different.

That is because the illuminated spot you see is giving off two different lights.

One is the pure narrow bandwidth called yellow.

The other is the agglomerate of all the other light in the beam, which is what I meant when I originally asked how much grey there is in the left hand sample.

 

[Hasan Özel]

53 minutes ago, studiot said:

But it doesn't, as I have tried to explain.

 

You are mixing up situations.

 

The way to see the colour of additive light sources is to shine them on a common area on a white screen or paper.
You don't stare into the beam.

 

What you then see in your two different situations looks different because it is different.

That is because the illuminated spot you see is giving off two different lights.

One is the pure narrow bandwidth called yellow.

The other is the agglomerate of all the other light in the beam, which is what I meant when I originally asked how much grey there is in the left hand sample.

 

I don't know the percentage of grey at left hand sample, I got it from internet research. But I can write as a RGB color them.

 

Edited April 4, 2018 by Hasan Özel

[studiot]

What are you doing there?

These are not the colour blocks you originally posted.

I didn't make clear that the "other light in the beam" ias not necessarily grey.

One of the colour models uses the neutral grey to adjust the apparent brightness of the pure colour. I think this is called the Hue Saturation Brightness (HSB) model.

A % grey can be added to any pure colour this way.

But that is a restriction of what can be added to any pure colour.

Adding any other mixture but the grey alters the received appearance of the colour ie changes the colour.

[Hasan Özel]

11 minutes ago, studiot said:

What are you doing there?

These are not the colour blocks you originally posted.

I didn't make clear that the "other light in the beam" ias not necessarily grey.

One of the colour models uses the neutral grey to adjust the apparent brightness of the pure colour. I think this is called the Hue Saturation Brightness (HSB) model.

A % grey can be added to any pure colour this way.

But that is a restriction of what can be added to any pure colour.

Adding any other mixture but the grey alters the received appearance of the colour ie changes the colour.

This is my fault, I update the picture 

But, I did not understand what do you mentioned. You want to say that monochromatic yellow(570-590 nm) and yellow=green + red have a different appearance like on a figure or a different thing ?

Edited April 4, 2018 by Hasan Özel

[studiot]

 

Look at the two blocks you have labelled 'pure cyan'

They appear different.

The one on the left appears to be pure cyan plus grey to me.

The one on the right appears to be a fair pure cyan

 

The two you have labelled pure yellow are more different and I think, though I may be wrong, that they are pure yellow plus some other non grey  light left and pure yellow (right).

 

I apologise, I now realise that they are your original colour blocks, I was too hasty.

Edited April 4, 2018 by studiot

[Hasan Özel]

31 minutes ago, studiot said:

 

Look at the two blocks you have labelled 'pure cyan'

They appear different.

The one on the left appears to be pure cyan plus grey to me.

The one on the right appears to be a fair pure cyan

 

The two you have labelled pure yellow are more different and I think, though I may be wrong, that they are pure yellow plus some other non grey  light left and pure yellow (right).

 

I apologise, I now realise that they are your original colour blocks, I was too hasty.

It's okay,not a problem 

Knowledge and science are sacred,the best way to move them forward is discussing. Live Science so long