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  1. #301
    lxdude's Avatar
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    Quote Originally Posted by Q.G. View Post

    Where is that red and green?
    The three filter layers cover a range of frequencies, not just precisely Red, Green and Blue. The filters overlap to an extent. Two of them overlap in the frequency range of pure yellow, allowing formation of colors which produce the sensation of yellow when viewed together. You can't figure that out?
    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.

  2. #302
    Photo Engineer's Avatar
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    Kodak Portra film has both a Green and Red sensitivity of about 2.0 relative log E with a maximum speed of 2.5, so it is pretty sensitive in the region of the visible spectrum of Sodium lamps. That is how it works to give us a yellow in the final print.

    I know color reproduction well enough to design films and papers and to be the person responsible for color reproduction of 3 major products AAMOF.

    To paraphrase Klaatu in the original movie "I know the math well enough to navigate between planets!" I used this in answer to one of the 24 or so PMs today about this thread. I hope that the quote is not lost on you all and explains my growing exasperation.

    PE

  3. #303
    lxdude's Avatar
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    Quote Originally Posted by Q.G. View Post
    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.
    As I said earlier, PE was explaining one method by which colors are employed to allow our brains to create the perception of other colors from them. He never said his explanation was comprehensive of all ways of seeing color.


    Get rid of that red herring about perception and reality.
    Why? It is about perceiving a color, which only a sensation. You allow that that Magenta is non-spectral; no single wavelength will cause us to perceive it. Our minds create it from Red and Blue. It is only a sensation. There is no Magenta wavelength, so it is not a natural color. So what's the problem with saying that other colors can be formed (in our heads) from combining colors?
    BTW, are you sure that herring's red? You might just be perceiving it that way.

    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.
    Get this, Q.G. Nobody has tried to explain everything about color using an additive or subtractive tri-color model.
    That is what you have missed.

    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?
    Exactly where?


    And that's why you always get involved in this sort of thing.
    Actually, I usually don't.
    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.

  4. #304
    eclarke's Avatar
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    If you're very scientific about a sucky photograph, it's still a sucky photograph...EC

  5. #305
    lxdude's Avatar
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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.
    You see what happens when those two colors are combined in additive system. Red and Green make Yellow. Do you deny that happens?
    In a subtractive system yellow is already there.

    No one on "the other side" ever said that yellow is not the color expression of a single wavelength, too. Only that the color can be perceived by combining Red and Green.
    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.

  6. #306
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    Quote Originally Posted by georg16nik View Post
    Q.G., I believe You can be a bit more kind to fellow APUG members
    Civility is underrated. And noticably absent from on-line forums. That's because we're raised (well, most of us are, at least) to be polite when talking to someone face-to-face (which is probably strongly reinforced in some of us the first time someone hits you for dissing them...). But in a 'virtual' conversation, there is no immediate feedback and it is much easier to ignore or shrug off a 'virtual' scolding than it is with an in-person scolding.

    It's the same reason many of us won't hesitate to cut in line on the highway whereas we would never do it in person. It's much easier to ignore the horn sounding than it is to ignore someone screaming at you in front of a hundred other people, some of which are equally impacted by your rudeness.

    Ed
    "I only wanted Uncle Vern standing by his new car (a Hudson) on a clear day. I got him and the car. I also got a bit of Aunt Mary's laundry, and Beau Jack, the dog, peeing on a fence, and a row of potted tuberous begonias on the porch and 78 trees and a million pebbles in the driveway and more. It's a generous medium, photography." -- Lee Friedlander

  7. #307
    lxdude's Avatar
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    Quote Originally Posted by Diapositivo View Post

    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.


    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.

    Fabrizio
    Yes, and what Q.G. does not understand is that no one disagrees with that. He somehow takes the explanation of additive color theory as applied to photo materials as a contradiction, which it is not. Both are true and can be demonstrated.
    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.

  8. #308
    lxdude's Avatar
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    Quote Originally Posted by Q.G. View Post

    The point about real or perceived (though interesting) is irrelevant here.
    Right. Because it's all perceived, whether as wavelength or color combination.
    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. #309
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    Quote Originally Posted by Neanderman View Post
    Civility is underrated. And noticably absent from on-line forums. That's because we're raised (well, most of us are, at least) to be polite when talking to someone face-to-face (which is probably strongly reinforced in some of us the first time someone hits you for dissing them...). But in a 'virtual' conversation, there is no immediate feedback and it is much easier to ignore or shrug off a 'virtual' scolding than it is with an in-person scolding.

    It's the same reason many of us won't hesitate to cut in line on the highway whereas we would never do it in person. It's much easier to ignore the horn sounding than it is to ignore someone screaming at you in front of a hundred other people, some of which are equally impacted by your rudeness.

    Ed
    And with that, perhaps it's time to close this thread. I've received too many reported post e-mails.



 

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