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  1. #281

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    Quote Originally Posted by Photo Engineer View Post
    Actually, a film exposed to pure sodium vapor lamp light sees a stream of photons with the energy level that causes the appearance of "yellow" light with a frequency of 600 nm (Red + Green). These photons excite two layers of a color film, the Red and Green layers, thus producing a "Yellow" record which is minus Blue. If anyone has another opinion, they can post it in detail. I have given the two applicable references, the Sodium vapor wavelength and the Kodak film sensitivity curves.

    I await another explanation that that stream of 600 nm photons.
    Why, you have already given one!


    You also revert to a multi-emulsion, filtered colour film to explain why an emulsion can respond to yellow light.

    And still that really nonsensical idea that 600 nm is "(Red + Green)"...
    Here is the light produced by a sodium lamp.

    Where is that red and green?

    It must be clear to you too, PE, that this tri-colour talk is all good and well, in a tri-colour context. And that your continued insistance on using it all the time is, plain and simple, wrong.
    If not, i believe you will never see the light.

    So back to Big Yellow as far as i'm concerned.

  2. #282

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    Quote Originally Posted by Ray Rogers View Post
    Can a wavelengh have more than one energy level?
    I'm not exactly sure what you mean by 'energy level' in this context. If you mean a photon's energy, then no. A photon with a given wavelength has a given energy and vice versa. And a photon with a given wavelength has a given frequency and vice versa.

    If you don't mean that, you'll have to clarify it.

    And veering incredibly far off course (from news about Kodak to quantum mechanics, wow!), to say that photons don't have wavelengths isn't quite correct. I'm tapping out on that though. If someone wants to know more about quantum mechanics and wave-particle duality, let me know. I feel QG doesn't particularly care about it though, so it's not worth my time.

  3. #283

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    Quote Originally Posted by Tim Gray View Post
    [...] And veering incredibly far off course (from news about Kodak to quantum mechanics, wow!), to say that photons don't have wavelengths isn't quite correct. I'm tapping out on that though. If someone wants to know more about quantum mechanics and wave-particle duality, let me know. I feel QG doesn't particularly care about it though, so it's not worth my time.
    You feel wrong. And Q.G. already knows about it.
    So yes, it would be a waste of time as far as i am concerned.

  4. #284

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    I feel wrong about what exactly? Pretty sure that photons (even a single photon) can exhibit wave-like behavior.

  5. #285

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    Quote Originally Posted by Tim Gray View Post
    I feel wrong about what exactly?
    You wrote this
    Quote Originally Posted by Tim Gray View Post
    [...] I feel QG doesn't particularly care about it though, so it's not worth my time.
    5 minutes ago, two posts up.
    You forget fast, don't you?

  6. #286

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    Oh, I said I don't particularly think you care about learning about quantum mechanics. It's clear at this point you are just trolling about so it's not really worth going into an in depth discussion about that. If you do have actual knowledge of it, it certainly doesn't appear that way by the manner you are expressing yourself.

    Sorry if your sentence was a bit hard to parse.

  7. #287

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    Quote Originally Posted by Tim Gray View Post
    I'm not exactly sure what you mean by 'energy level' in this context. If you mean a photon's energy, then no. A photon with a given wavelength has a given energy and vice versa. And a photon with a given wavelength has a given frequency and vice versa.

    If you don't mean that, you'll have to clarify it.

    And veering incredibly far off course (from news about Kodak to quantum mechanics, wow!), to say that photons don't have wavelengths isn't quite correct. I'm tapping out on that though. If someone wants to know more about quantum mechanics and wave-particle duality, let me know. I feel QG doesn't particularly care about it though, so it's not worth my time.
    When I enquired about red light exposing unsensitized emulsions, one of the possible explanations was that practically any wavelength could make the grains developable, if it had sufficient energy.

    Not being coherent in physics,
    I just assumed that it was just something else I did not understand about light.

    The other explanations were logical enough to satisify me and
    I never solved the mystery of what that explanation was really all about.

    Thinking about now,
    I wonder if the "energy" of a wavelength is somehow concentrated by increasing it's coherency?

  8. #288

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    Quote Originally Posted by Tim Gray View Post
    Oh, I said I don't particularly think you care about learning about quantum mechanics. It's clear at this point you are just trolling about so it's not really worth going into an in depth discussion about that. If you do have actual knowledge of it, it certainly doesn't appear that way by the manner you are expressing yourself.

    Sorry if your sentence was a bit hard to parse.
    No, Tim.
    Talk like that is "just trolling about".

    I have kept to the matter in hand in each and every single post i have made.
    If you want to discuss quantum mechanics, that's fine with me. Let's!
    If you think that i don't care about it, suggest that i don't know, and don't want to know, about it, you're being incredibly presumptuous. And very wrong to boot.
    And passing your inability to understand off as someone else's inability to make something clear to you? Well... Don't.

  9. #289
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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 06:28 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

  10. #290

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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.



 

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