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  1. #261

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    Quote Originally Posted by Photo Engineer View Post
    If you look here: http://en.wikipedia.org/wiki/Sodium-vapor_lamp you see the spectrum of Sodium vapor at 600 nm. If you look at Kodak's web site here: http://www.kodak.com/global/en/profe...4050/e4050.pdf you will see that film typically has sensitivity at 600 nm. That is how a film can see the light of a Sodium lamp.

    PE
    But is it:

    Quote Originally Posted by Photo Engineer
    "2 photons with a Green energy level and a Red energy level,"
    or

    Quote Originally Posted by Photo Engineer
    "one photon with an intermediate energy level between Red and Green captured in 2 layers"
    ?

    It's, of course, neither.

  2. #262

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    Quote Originally Posted by Tim Gray View Post
    So it's how 'color sensitive thingies' (which I shortened to 'detectors') and photon energy interact.
    Why, yes.

    Quote Originally Posted by Tim Gray View Post
    Um, no? Photon energy, frequency, and wavelength are all essentially the same quantity, expressed in different ways. It's not anything goes.
    Anything goes talk is that
    Quote Originally Posted by Tim Gray
    they just have an energy/wavelength/frequency, depending on how you want to think about it.
    Energy, frequency and wavelength are indeed three different aspects of an entity.
    They're not the same "quantity" expressed in different ways.

  3. #263

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    Quote Originally Posted by Ray Rogers View Post
    I assume you are talking about B/W emulsion w/o presumed sensitivity in that region...

    "Ordinary" (meaning blue sensitive, non-spectrally sensitized) emulsions
    are also sensitive to red!

    I know one possible explanation,
    but I suspect your POV might related here as an additional explanation.

    I guess its probably too complicated for you (Q. G.) to show us how it works?
    Migh, migh... Ray!

  4. #264

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    Quote Originally Posted by Q.G. View Post
    Energy, frequency and wavelength are indeed three different aspects of an entity.
    They're not the same "quantity" expressed in different ways.
    Sorry, I should have been pedantically precise in my language. The energy of a photon is related to it's frequency by the expression E = h nu, where h is Planck's constant and nu is the frequency. Frequency and wavelength are related through another expression nu = c / lambda, where c is a constant (speed of light) and lambda is the wavelength.

    A photon with a given energy has a frequency and wavelength that are dependent only on the energy. While they have different physical meanings (obviously - one is an energy, one is a length, and one is frequency), they are not independent quantities; set one and the others are fixed.

    As to the first part - so photons don't have colors. They have energies, and color is how the detector 'interprets' that energy.

  5. #265

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    Quote Originally Posted by Tim Gray View Post
    Sorry, I should have been pedantically precise in my language. [...]
    If you think it's about language, the optics 1.0.1. explanation i snipped away would be rather empty and redundant.


    Quote Originally Posted by Tim Gray View Post
    As to the first part - so photons don't have colors. They have energies, and color is how the detector 'interprets' that energy.
    How many times do you want to have that repeated? How many times do you want to repeat that yourself?

    Photons also have wavelengths (well... they don't. Waves have wavelengths), and colour is how the detector 'interprets' that wavelength.

    Photons also have [etc.]

  6. #266
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    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.

    PE

  7. #267

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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.

  8. #268

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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.

  9. #269

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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.

  10. #270

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



 

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