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  1. #281
    Diapositivo's Avatar
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    If one, like me, wanted to learn something from this soon-to-become-a-row discussion, I think he would distill its essence more or less this way:

    - Correct me if I am wrong in substance (I know I am wrong in form) -

    Q.G. is probably telling us that the spectrum of light visible to human beings is composed of many more colours than the three, RGB, fundamental colours of additive synthesis. Something like yellow light exists, or orange light for that matter.

    The way photographic technology renders colours (we limit ourselves here to additive synthesis, and we imagine coloured light as projected by a transparency) is to use only three basic colours, RGB. In fact, if the white light of a projector is filtered through the red and green layers of a slide, and no blue light is allowed to pass by the slide, then the two flows of red and green superimposed will create in our eyes the effect of yellow.

    If I get it right, Q.G. is saying that even if it is technologically feasible to make yellow light as a superimposition of red light and green light, "yellow" light exists in nature independently from red and green. Or to put it in another way, the three colour theory is something that works in practice, but it is not the way things are "in nature". "In nature" there is a certain portion of the white spectrum that we humans perceive as yellow because it is of a certain wavelength and not because it is the result of the superimposition of blue and green light.

    On the other hand, magenta is a colour that the human eye cannot perceive as a portion of the white light spectrum. We can find a way to reproduce magenta using the three colour theory, but that is not a colour that we "find" anywhere in the way the human light perceives the light. Is it that?

    So the three colour theory is a way to reproduce colour but it is not, so to speak, the intimate deep physics nature of colours, it is just a technology that works. Other technological means would be conceivable (regardless of whether they have been realised) to reproduce colours and colours are explainable regardless of the technology devised to reproduce them.

    It is this the question over which this debate revolves?

    Or please do clarify which exactly your differences are, so that we can take part in the row as well

    Fabrizio
    Last edited by Diapositivo; 02-09-2011 at 05:28 PM. Click to view previous post history.
    Fabrizio Ruggeri fine art photography site: http://fabrizio-ruggeri.artistwebsites.com
    Stock images at Imagebroker: http://www.imagebroker.com/#/search/ib_fbr

  2. #282

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    Quote Originally Posted by Diapositivo View Post
    If one, like me, wanted to learn something from this soon-to-become-a-row discussion, I think he would distill its essence more or less this way: [...]

    On the other hand, magenta is a colour that the human eye cannot perceive as a portion of the white light spectrum. We can find a way to reproduce magenta using the three colour theory, but that is not a colour that we "find" anywhere in the way the human light perceives the light. Is it that?
    Pretty accurate, Fabrizio.

    Except for the bit about magenta. Not that you are wrong, but it could perhaps do with a clarification.
    Magenta is a colour that doesn't exist as a single portion of the spectrum, but still something we can see as a combination of portions of the spectrum. I.e. it too is a colour that exists, and we find, in nature.

    Magenta, by the way, became topic of discussion, because in a thread about orthochromatic film, or rather how that could be emulated filtering out the red portion of the spectrum, this confused additive and subtractive tri-colour talk emerged, and resulted in the suggestion that you could record magenta, even though all the red was taken out of the equation.
    The simple truth that there is no magenta when there is no red, that magenta is not a spectral colour, apparently has confused some easily confusable and gullible souls so much that they still think that jibing about "magenta is not a colour" is fun. Which it is. Especially since they still don't see that the joke is on them.

  3. #283

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    Quote Originally Posted by Q.G. View Post
    I have kept to the matter in hand in each and every single post i have made.
    That's not how I've read quite a few post of yours to me and others. I'm sorry if I've presumed anything about you.

    If I understand this whole argument over color and light, it would seem as if one side would like to say that '600 nm light' = 'yellow light', i.e. yellow is an intrinsic property of that light. It seems like the other side would like to say that we perceive 600 nm light as yellow, i.e. 'yellow' is not an intrinsic property of light, it's wavelength is.

    If you take those two sides to the next step, the first says magenta isn't a real color because you can't make magenta with one single wavelength of light. The other side would say that's not true because color is 'all in our heads'. I think they would agree with the statement that magenta does not correspond to a single wavelength of light, but that doesn't disqualify it from being a color.

  4. #284
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    Quote Originally Posted by Q.G. View Post
    And there's the problem.

    You would think so. But... That's what this is all (the different threads this has surfaced in) about.
    What problem? You're the only one who has a problem with it, as far as I can tell.


    Completely irrelevant it is here too.
    And when pushed despite of that, misleading and incorrect also.
    Irrelevant to what?
    Misleading, incorrect...how? Compared to what?

    Duh...

    So you do not see what's going on.

    You don't see how yellow is not a mix of whatever two colours, but the colour a photon can have. A photon an emulsion shows a response to, despite it not being a tri-colour emulsion.
    Very presumptive, you are.
    I of course do know that combining two frequencies does not result in reality in their annihilation and the production of a third frequency. But color is a sensation. What we perceive as color does not exist. Only EM radiation of various frequencies. In color photography, emulsions are filtered (frequencies removed) to control the frequency range to which the emulsion is sensitive, or to reduce sensitivity to a frequency or frequencies.
    Functionally, though, combining two colors will result in the perception of another color. Color photographs are for looking at. Color materials are manufactured using methods which work. They use those methods, and we get to look at the all the purty colors.

    You don't see that the tri-colour trickery has to be employed to differentiate between the colours, so you can use panchromatic B&W emulsions to create something you can perceive as separate colours.
    Even more presumptive. Why would I talk about tri-color methods, otherwise? Do you think I don't know about multi-layer color materials?

    You don't see that it is all irrelevant, because we were not talking about anything like this. Until someone brought it up to give some 'relevance' to completely irrelevant comments.
    PE said something like "Sorry guys, this is way off topic". I pointed out an inadvertent error; further discussion ensued. You participated and expanded the discussion. So what's your beef?

    Round and round and round and round and...
    The going is remarkably tough on APUG today.
    That's how it usually is when you're involved.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  5. #285

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    Quote Originally Posted by Tim Gray View Post
    That's not how I've read quite a few post of yours to me and others. I'm sorry if I've presumed anything about you.

    If I understand this whole argument over color and light, it would seem as if one side would like to say that '600 nm light' = 'yellow light', i.e. yellow is an intrinsic property of that light. It seems like the other side would like to say that we perceive 600 nm light as yellow, i.e. 'yellow' is not an intrinsic property of light, it's wavelength is.
    Those could be two sides. But they are not the two sides in this ongoing thingy.

    The other side in this claims that yellow is an additive or subtractive colour, the result of a combination of two other colours.

    The point about real or perceived (though interesting) is irrelevant here.

    Quote Originally Posted by Tim Gray View Post
    If you take those two sides to the next step, the first says magenta isn't a real color because you can't make magenta with one single wavelength of light. The other side would say that's not true because color is 'all in our heads'. I think they would agree with the statement that magenta does not correspond to a single wavelength of light, but that doesn't disqualify it from being a color.
    Indeed.
    But as said, not what this is about.

  6. #286
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    Ultimately it boils down to wether you are a Goethe person or a Newton person. Sort of like Elvis and the Beatles. You can like both, but you can't like them the same.
    That's just, like, my opinion, man...

  7. #287

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    Quote Originally Posted by Q.G. View Post
    The other side in this claims that yellow is an additive or subtractive colour, the result of a combination of two other colours.
    And the first side says...?

  8. #288
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    Quote Originally Posted by Q.G. View Post
    Who said that?

    But yes, all sensors also sense themselves.
    OMG, they're self-aware!



    Since when do photons have a wavelength or frequency?
    Well, since the Big Bang, at least.
    Oh, right. From the pedantic, narrow, apparently-unable-to descend-to-the-level-upon-which-the-rest-of-us-can-communicate point of view, no, they don't have those things.

    You could go down that road, and not be done talking for many years.
    You go ahead. We'll catch up later. Much later.

    You could also assume some relation between observation and the observed.
    Heisenberg would be so relieved to know you agree with him.
    I do use a digital device in my photographic pursuits when necessary.
    When someone rags on me for using film, I use a middle digit, upraised.

  9. #289

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    Quote Originally Posted by lxdude View Post
    What problem? You're the only one who has a problem with it, as far as I can tell.
    I am perhaps the only one taking issue with it. But the problem belongs to all of those who believe PE's explanation of colour.
    They are being lead into something worse than ignorance: false knowledge.


    Quote Originally Posted by lxdude View Post
    Irrelevant to what?
    Misleading, incorrect...how? Compared to what?
    You have read the discussion, have you not?

    Quote Originally Posted by lxdude View Post
    Very presumptive, you are.
    I of course do know that combining two frequencies does not result in reality in their annihilation and the production of a third frequency. But color is a sensation. What we perceive as color does not exist. Only EM radiation of various frequencies. In color photography, emulsions are filtered (frequencies removed) to control the frequency range to which the emulsion is sensitive, or to reduce sensitivity to a frequency or frequencies.
    Functionally, though, combining two colors will result in the perception of another color. Color photographs are for looking at. Color materials are manufactured using methods which work. They use those methods, and we get to look at the all the purty colors.
    Apparently not presumptuous, but acutely observative.


    Get rid of that red herring about perception and reality.
    Whether you call it colour, energy or frequency is irrelevant. Irrelevant, because it doesn't change anything about the error that is trying to explain everything about colour using an additive or subtractive tri-colour model.
    That's what you have missed.


    Quote Originally Posted by lxdude View Post
    Even more presumptive. Why would I talk about tri-color methods, otherwise? Do you think I don't know about multi-layer color materials?
    Why indeed. Why would anyone?
    That's the entire point. Tell PE.

    But have you noticed that multi-layer colour materials were pressed into service to explain something that has nothing to do with multi-layer colour materials?
    Have you managed to keep the two apart?

    Quote Originally Posted by lxdude View Post
    PE said something like "Sorry guys, this is way off topic". I pointed out an inadvertent error; further discussion ensued. You participated and expanded the discussion. So what's your beef?

    That's how it usually is when you're involved.
    And that's why you always get involved in this sort of thing.

  10. #290

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    Quote Originally Posted by Tim Gray View Post
    And the first side says...?
    Quote Originally Posted by Tim Gray View Post
    one side would like to say that '600 nm light' = 'yellow light' [...]
    You do forget in a hurry!



 

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