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  #31  
Old December 21st, 2017, 07:11 AM
James Lemon James Lemon is offline
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Originally Posted by Doug Kerr View Post
I think the underlying dilemma here is that the "color" we measure of an instance of light by objective measurements of the spectral distribution of the light and subsequent mathematical processing, and the "color" that is a sensation of a human viewing that light, are not the same thing.

The "color" we measure, objectively, is a predictor of the "color" that the "average" human viewer would perceive upon viewing that light.

And in fact the process I described earlier really uses a model of the response of the "average" human visual system to light components of different wavelengths. The three "matching curves" I describe are derived from the curves that describe the response of the three kinds of cone receptors in the "average" human visual system.
Well, to be more honest, it works in the other direction. We cannot (very well) measure the response curves of the eye. In fact we infer those curves from the related "matching curves", which are arrived at by empirical testing.
Now would it be more "honest" and "clear" if we did not use the term "color" to refer to the result of this measurement process, reserving that word for the human perception? Sure.

Perhaps we would refer to the result of that measurement as the "protocolor" of the light. Then one could say, "You know, we cannot measure the color of light. All we can measure is its protocolor."

But I did not get the chance to suggest that to the CIE committee that devised the objective definition of "color" and the scheme for determining it. And I would not at all doubt that discussions of that possibility were held. But clearly the decision was to call the defined and measurable metric "color".

And perhaps in my contributions to the discussion here I did not clearly enough illuminate and indicate my recognition that indeed the "color" seen by a human and the "color" measured with an objective process are not the same thing (but we hope they are closely relatable, for the "average" viewer).

This is not the only place in science where we have this duality. Another case is in the "loudness" of sound. That too is a matter of human perception. Yet we use an instrument to measure the acoustic pressure wave arriving at a viewer's location and deliver its finding as the "loudness" of the sound at that point. And, just as in the case of "color", the working of that measurement has "baked in" a model of a certain (somewhat subtle) aspect of human hearing, of course for the "average" listener.

So to answer James' recent question, color (in sense 1) is a fact, and color (in sense 2) is a perception.




Best regards,

Doug
Doug

Radiation can be measured but light and color is a subjective human sensation and therefore can not be measured.

James
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  #32  
Old December 21st, 2017, 08:13 AM
Doug Kerr Doug Kerr is offline
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Hi, James,

Quote:
Originally Posted by James Lemon View Post
Doug

Radiation can be measured but light and color is a subjective human sensation and therefore can not be measured.
So, if I were writing a specification for traffic signal heads, lets say a "red" one, what property of the visible radiation from that head should I specify, and in what terms is that property expressed?

Best regards,

Doug
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  #33  
Old December 21st, 2017, 08:23 AM
fahim mohammed fahim mohammed is offline
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Ummmm....

Galaxies approaching or receding. Doppler shifts. Young or old stars. Spectral analysis.
EMW...characteristics...wave length, frequency, energy emission.Temperature... reflective refractive, distributive and absorption characteristics of objects..etc. somethings to think about!

What it is can be measured, paramterized. What it has been named? Red could have been named blue!

What and how a certain EM wave affects/effects our senses is a ‘ feeling ‘...what effect it produces might depend on the observer..serene, aggressive, danger, calm, Love etc is a perception.

Roses are green, leaves are indigo. Certainly Mr. Kelvin would be perplexed with photographers.

p.s I am sure Mr. Doppler is following this conversation with interest.

p.p.s. My daughter who is sitting next to me and is a consultant pathologist..reminds me to mention ‘ color’ as ‘ perceived ‘ by doctors and patients. e.g what was the color of your stool? Fact or perception, she asks...it could be important in follow-up of the patient. Red, yellowish, grey, black...?
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  #34  
Old December 21st, 2017, 09:43 AM
James Lemon James Lemon is offline
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Originally Posted by Doug Kerr View Post
Hi, James,



So, if I were writing a specification for traffic signal heads, lets say a "red" one, what property of the visible radiation from that head should I specify, and in what terms is that property expressed?

Best regards,

Doug
Doug

I would suggest that the color red is a poor choice for a traffic light considering that automobile tail lights are also red.

James
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  #35  
Old December 21st, 2017, 10:55 AM
Asher Kelman Asher Kelman is offline
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James,

Allow me to put this whole discussion in fair context.

We can identify a person fairly accurately by just observing them or listening to their speech. By contrast, we can recognize that same person with far greater certainty by instrumentation: retina scan, voice analysis, iris scan or fingersprinymts.

That is analogous to color identity.

If we call "Kolor" the system of prediction of the human response to the mixing of 3 light beams of defined wavelength and intensity, we could use this instrument to determine accurately what color patch, (of tens of thousands offered), most humans would identify as the color, (simply by their natural perception), most closely matches to that light mixture. We do not have a separate term "Kolor", as by usage, the Kolor or graphical X,Y,Z coordinates have become, incorrectly to be called, color too.

However, the "Kolor" predictive and recognition system is rigorous science and their Skokie can be measured. We just happen to use the word "color", just as the British use the verb, "to Hoover" to reflect vacuum cleaning a floor, when "Hoover" can only rightfully apply to products made by the Hoover Corporation! Similarly we can say that "hydrogen loves oxygen or "God love man" when we are not referring to love making between opposite sexes.

Words evolve so as an example, today, the word "color" can refer to the color temperature in Degrees Kelvin of light or steel or perception or a position on a gamut of coordinates of 3 contributing wavelengths of electromagnetic radiation forming a unique chromaticity in a field of chromaticities bounded by by XYZ coordinates of wavelength, (or by the equivalent perceived chromaticity of a broader spread of different wavelengths).

Hey, my friend, if you ever wish to tell a depressed homosexual that he is no longer "gay", go ahead and be historically correct, for the older limited meaning of "gay" referring to "spirited happy mood". However, such insistence in epistemological correctness, serves no practical purpose today, as the only meanings that are relevant are those in common use.

Asher
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Last edited by Asher Kelman; December 22nd, 2017 at 12:24 AM.
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  #36  
Old December 21st, 2017, 01:16 PM
James Lemon James Lemon is offline
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Originally Posted by Asher Kelman View Post
James,

Allow me to put this whole discussion in fair context.

We can identify a person failrly accurately by just observing them or listening to their speech. By contrast, we can recognize that same person with far greater certainty by instrumentation: retina scan, voice analysis, iris scan or fingersprinymts.

That is analogous to color identity.

If we call "Kolor" the system of prediction of the human response to the mixing of 3 light beams of defined wavelength and intensity, we could use this instrument to determine accurately what color patch, (of tens of thousands offered), most humans would identify as the color, (simply by their natural perception), most closely matches to that light mixture. We do not have a separate term "Kolor", as by usage, the Kolor or graphical X,Y,Z coordinates have become, incorrectly to be called, color too.

However, the "Kolor" predictive and recognition system is rigorous science and their Skokie can be measured. We just happen to use the word "color", just as the British use the verb, "to Hoover" to reflect vacuum cleaning a floor, when "Hoover" can only rightfully apply to products made by the Hoover Corporation! Similarly we can say that "hydrogen loves oxygen or "God love man" when we are not referring to love making between opposite sexes.

Words evolve so as an example, today, the word "color" can refer to the color temperature in Degrees Kelvin of light or steel or perception or a position on a gamut of coordinates of 3 contributing wavelengths of electromagnetic radiation forming a unique chromaticity in a field of chromaticities bounded by by XYZ coordinates of wavelength, (or by the equivalent perceived chromaticity of a broader spread of different wavelengths).

Hey, my friend, if you ever wish to tell a depressed homosexual that he is no longer "gay", go ahead and be historically correct, for the older limited meaning of "gay" referring to "spirited happy mood". However, such insistence in epistemological correctness, serves no practical purpose today, as the only meanings that are relevant are those in common use.

Asher
Asher

Colour has always been about perception, it still is and always will be. It does not matter if you are
Microsoft, Apple, Adobe, Internet Explorer, Safari, Fire Fox or Asher Kelman it is perceived differently in all cases. I am having a mood this New Years Eve and everyone has to come dressed as a color, you and everyone are invited!!!

James.
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  #37  
Old December 21st, 2017, 01:41 PM
Asher Kelman Asher Kelman is offline
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Originally Posted by James Lemon View Post
Asher

Colour has always been about perception, it still is and always will be. It does not matter if you are
Microsoft, Apple, Adobe, Internet Explorer, Safari, Fire Fox or Asher Kelman it is perceived differently in all cases. I am having a mood this New Years Eve and everyone has to come dressed as a color, you and everyone are invited!!!

James.
Please, act as the friend you are and cease to trvialize the learned responses from Doug Kerr and my own efforts to explain your dilemmas.

Can you have the kindness to actually read what I wrote and not trivialize my effort. I have spent a lot of time addressing your questions. I have leveraged my knowledge of color (from my physics expertise and the insight I have as a trained biological scientist, professor and medical specialist with many decades of experience), to explain to you what color is in modern vocabulary and how you can reconocile perception with science. However, you refuse to pay attention to the facts.

This is a template for why the republicans in the USA do not understand science and have in fact in the last week banned, (in scientific agencies), the use of the term "evidence-based', "fetus", "diversity" and "science-based" so as not to clash with sensitiviities of right wind tropes, ignorance, unkindness and prejudice.

Asher
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  #38  
Old December 21st, 2017, 02:21 PM
James Lemon James Lemon is offline
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Originally Posted by Asher Kelman View Post
Please, act as the friend you are and cease to trvialize the learned responses from Doug Kerr and my own efforts to explain your dilemmas.

Can you have the kindness to actually read what I wrote and not trivialize my effort. I have spent a lot of time addressing your questions. I have leveraged my knowledge of color (from my physics expertise and the insight I have as a trained biological scientist, professor and medical specialist with many decades of experience), to explain to you what color is in modern vocabulary and how you can reconocile perception with science. However, you refuse to pay attention to the facts.

This is a template for why the republicans in the USA do not understand science and have in fact in the last week banned, (in scientific agencies), the use of the term "evidence-based', "fetus", "diversity" and "science-based" so as not to clash with sensitiviities of right wind tropes, ignorance, unkindness and prejudice.

Asher
Asher

Excuse me but I did not ask you any questions in regards to this. You can except the evidence presented or not but I really don't care one way or the other. They must of had a good reason to ban all those sales pitches?

James
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  #39  
Old December 21st, 2017, 02:23 PM
Asher Kelman Asher Kelman is offline
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What sales pitches are you referring to?
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  #40  
Old December 21st, 2017, 04:05 PM
Doug Kerr Doug Kerr is offline
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Hi, James,

Quote:
So, if I were writing a specification for traffic signal heads, lets say a "red" one, what property of the visible radiation from that head should I specify, and in what terms is that property expressed?

Quote:
Originally Posted by James Lemon View Post
Doug

I would suggest that the color red is a poor choice for a traffic light considering that automobile tail lights are also red.
Oh, you have no idea. OK.

Best regards,

Doug
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  #41  
Old December 21st, 2017, 04:32 PM
James Lemon James Lemon is offline
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Quote:
Originally Posted by Doug Kerr View Post
Hi, James,


Oh, you have no idea. OK.

Best regards,

Doug


Doug

You asked a hypothetical question and I gave you an answer. It is obvious you do not understand the full implication of my answer.

James
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  #42  
Old December 21st, 2017, 06:42 PM
Doug Kerr Doug Kerr is offline
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Hi, Jerome,

So, what kinds of things can you measure with this?


I find this screen especially interesting (ignore the arrow - it's not mine):


Thanks.

Best regards,

Doug
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  #43  
Old December 21st, 2017, 08:19 PM
James Lemon James Lemon is offline
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Quote:
Originally Posted by Doug Kerr View Post
Hi, Jerome,

So, what kinds of things can you measure with this?


I find this screen especially interesting (ignore the arrow - it's not mine):


Thanks.

Best regards,

Doug
Doug

They look magical!! Do they sell short wave length types for women?

James
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  #44  
Old December 21st, 2017, 09:36 PM
Doug Kerr Doug Kerr is offline
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Hi, James,

Quote:
Originally Posted by James Lemon View Post
Doug

They look magical!
I think they are. I mean after all, they ... Oh never mind.

Quote:
Do they sell short wave length types for women?
Mebbe so. That might be of special interest for that famous film star Ultra Violet.

Best regards,

Doug
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  #45  
Old December 22nd, 2017, 05:47 AM
Jerome Marot Jerome Marot is offline
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Quote:
Originally Posted by Doug Kerr View Post
Hi, Jerome,

So, what kinds of things can you measure with this?


I find this screen especially interesting (ignore the arrow - it's not mine):


Thanks.

Best regards,

Doug

You surprised me twice in this thread, Doug. First you suggested to sacrifice a chicken when I just posted an image of the Sekonic C700 to get the discussion going. In truth, I was only expecting comments on the necessity to control the illuminant (what that device is designed to control and is a necessity in this time of solid state light fixtures...) and possibly comments on the limitation of the human vision system which is only capable to detect 3 bands while this device detects 500. Second, you are asking a question for which you obviously know the answer.

You see, I normally pay attention to little details and this is not the device I posted. This is the professional version (Sekonic has 3 different versions). Then I noticed that the second image which you use is directly linked from the manufacturer web site with all the explanations you could need (the one with the arrow). That page is where that image is linked from:
https://www.sekonic.com/united-state.../overview.aspx
That page has answers to all the questions you asked and more and in particular a description of the values of the picture with the arrow. So why ask them from me?
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  #46  
Old December 22nd, 2017, 06:46 AM
James Lemon James Lemon is offline
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Quote:
Originally Posted by Asher Kelman View Post
Another from Wendy in the Desert!



Wendy Kelman: Desert Garden Sunset






Asher

Reuters reports that researchers from Arizona State University in Tempe have determined there is a gene that allows us to see the color red, and that gene comes in a high number of variations.

Because the gene sits on the X chromosome—and women have two X chromosomes and so two copies of this gene, compared with only one for men—the gene aids women’s ability to perceive the red-orange color spectrum. Also, in general, women are better at differentiating between close range of colors while men are better at recognizing fine details in a moving object.

James
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  #47  
Old December 22nd, 2017, 07:11 AM
Jerome Marot Jerome Marot is offline
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Originally Posted by James Lemon View Post
Asher

Reuters reports that researchers from Arizona State University in Tempe have determined there is a gene that allows us to see the color red, and that gene comes in a high number of variations.

Because the gene sits on the X chromosome—and women have two X chromosomes and so two copies of this gene, compared with only one for men—the gene aids women’s ability to perceive the red-orange color spectrum. Also, in general, women are better at differentiating between close range of colors while men are better at recognizing fine details in a moving object.

James
I can't find an article from the Arizona State University in Tempe over that particular subject nor a report from Reuters. There are, of course, numerous other scientific papers over that subject and reports in the non-scholar press, like these:

https://theneurosphere.com/2015/12/1...-more-colours/

http://www.iflscience.com/brain/tetr...illion-colors/

http://www.bbc.com/future/story/2014...r-human-vision

http://discovermagazine.com/2012/jul...r-human-vision
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  #48  
Old December 22nd, 2017, 07:22 AM
James Lemon James Lemon is offline
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Originally Posted by Jerome Marot View Post
I can't find an article from the Arizona State University in Tempe over that particular subject nor a report from Reuters. There are, of course, numerous other scientific papers over that subject and reports in the non-scholar press, like these:

https://theneurosphere.com/2015/12/1...-more-colours/

http://www.iflscience.com/brain/tetr...illion-colors/

http://www.bbc.com/future/story/2014...r-human-vision

http://discovermagazine.com/2012/jul...r-human-vision
Jerome
Apparently the study was reported in the American Journal of Human Genetics. The following link may help you in finding the study.

http://webcenters.netscape.compuserv...rs_differently
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  #49  
Old December 22nd, 2017, 07:55 AM
Doug Kerr Doug Kerr is offline
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Hi, Jerome,

Quote:
Originally Posted by Jerome Marot View Post
You surprised me twice in this thread, Doug. First you suggested to sacrifice a chicken when I just posted an image of the Sekonic C700 to get the discussion going. In truth, I was only expecting comments on the necessity to control the illuminant (what that device is designed to control and is a necessity in this time of solid state light fixtures...) and possibly comments on the limitation of the human vision system which is only capable to detect 3 bands while this device detects 500. Second, you are asking a question for which you obviously know the answer.

You see, I normally pay attention to little details and this is not the device I posted. This is the professional version (Sekonic has 3 different versions). Then I noticed that the second image which you use is directly linked from the manufacturer web site with all the explanations you could need (the one with the arrow). That page is where that image is linked from:
https://www.sekonic.com/united-state.../overview.aspx
That page has answers to all the questions you asked and more and in particular a description of the values of the picture with the arrow. So why ask them from me?
Oh, I was just being silly. The prerogative of a dotard.

Best regards,

Doug
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  #50  
Old December 22nd, 2017, 08:38 AM
Asher Kelman Asher Kelman is offline
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Moved from thread on "Pictures from Wife's"



Quote:
Originally Posted by James Lemon View Post


Wendy Kelman: Desert Garden Sunset






Asher

Reuters reports that researchers from Arizona State University in Tempe have determined there is a gene that allows us to see the color red, and that gene comes in a high number of variations.

Because the gene sits on the X chromosome—and women have two X chromosomes and so two copies of this gene, compared with only one for men—the gene aids women’s ability to perceive the red-orange color spectrum. Also, in general, women are better at differentiating between close range of colors while men are better at recognizing fine details in a moving object.

James

As you selected Wendy's sunset picture for comment on possible enhanced light perception by genetic dispositions, I will let her know her work caught your eye. 🙏


.....and in very low light both men and women may see more subtle changes as the rods may also now get used to expand the perception of color.

Asher
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Last edited by Asher Kelman; December 22nd, 2017 at 01:25 PM.
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  #51  
Old December 22nd, 2017, 08:48 AM
Jerome Marot Jerome Marot is offline
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Jerome
Apparently the study was reported in the American Journal of Human Genetics. The following link may help you in finding the study.

http://webcenters.netscape.compuserv...rs_differently

There it is. It is an article from 2004:

http://www.cell.com/ajhg/fulltext/S0002-9297(07)63309-6
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  #52  
Old December 22nd, 2017, 08:50 AM
Jerome Marot Jerome Marot is offline
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Quote:
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Oh, I was just being silly. The prerogative of a dotard.
Don't do that or I'll be worried that someone from dpreview has hacked your account and is posting in your name.
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  #53  
Old December 26th, 2017, 05:05 AM
Peter Dexter Peter Dexter is offline
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It was interesting to me to learn from reading Andrew Parker's book The Seven Deadly Colors that color has a molecular basis. Paleontologists now use that fact to extrapolate the colors of dinosaur feathers.
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  #54  
Old December 27th, 2017, 07:59 PM
Asher Kelman Asher Kelman is offline
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It was interesting to me to learn from reading Andrew Parker's book The Seven Deadly Colors that color has a molecular basis. Paleontologists now use that fact to extrapolate the colors of dinosaur feathers.

Today, with DNA analysis, even dinosaurs cant hide from detectives. I'd give up on being a criminal.


Asher
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