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Thread: Does black exist?

  1. #61
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    Quote Originally Posted by Darrell View Post
    Very interesting. Could you explain a bit or point me towards some information on that? From the few minutes I spent looking into it Violet is a spectral color (single wavelength) while Mauve is a shade of purple and is a composite color (a combination of wavelengths).
    I think the problem here is that there is violet, a spectral colour, and "violet", the approximation to that spectral colour produced from red, green and blue phosphors/LEDs or CMYK printer pigments - and the latter violet is a shade of bluish purple, somewhere around RGB (127,0,255). The original mauvine dye looked a lot like that kind of violet, to my eye. Unfortunately, the label "mauve" seems to nowadays be applied to a redder and less saturated purple, around RGB (225, 175, 255). Hence my previous comment that I'm unconvinced that mauve and violet are the same hue.

    Grant Hutchison

  2. #62
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    Quote Originally Posted by profloater View Post
    Picky but that depends what colour filter you use, a brown transmission filter like a slide of a muddy scene will give you brown or indeed any colour so it must be in the rainbow as white light. Our eyes interpret mixes of frequencies.
    It is my understanding that faint orange light appears brown when surrounded by a bright background.

  3. #63
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    Quote Originally Posted by Hornblower View Post
    My bold. That is a grossly oversimplified attempt at a description. That mauve is clearly light gray with an admixture of violet,
    Ay, there's the rub.

    What frequency is the "grey" you refer to? It's not "an equal combination of r g and b", since self-evidently, this does not have an equal combination.
    You can't use the colour "grey" without acknowledging that colour occurs in the brain, not in the light.

  4. #64
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    Quote Originally Posted by grant hutchison View Post
    I think the problem here is that there is violet, a spectral colour, and "violet", the approximation to that spectral colour produced from red, green and blue phosphors/LEDs or CMYK printer pigments - and the latter violet is a shade of bluish purple, somewhere around RGB (127,0,255).
    RGB is one colour space; another is HSB.


    They're the same hue, since I chose them to be.

    They are both Hue 300 and Saturation 68, just one is Brightness 7 and the other is Brightness 100: HSB (300,68,7) vs. HSB (300,68,100)




    Quote Originally Posted by grant hutchison View Post
    The original mauvine dye looked a lot like that kind of violet, to my eye. Unfortunately, the label "mauve" seems to nowadays be applied to a redder and less saturated purple, around RGB (225, 175, 255). Hence my previous comment that I'm unconvinced that mauve and violet are the same hue.
    Let'snot get hung up on the labels. I could have chosen one of dozens of other labels for that colour, or chosen no label at all.
    There is a colour that has the same hue as violet, yet is not the same colour.
    Last edited by DaveC426913; 2019-Sep-26 at 03:05 PM.

  5. #65
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    Quote Originally Posted by DaveC426913 View Post
    RGB is one colour space; another is HSB.
    Yes. In fact, I already mentioned the related concept of HSL.

    Quote Originally Posted by DaveC426913 View Post
    They're the same hue, since I chose them to be.

    They are both Hue 300 and Saturation 68, just one is Brightness 7 and the other is Brightness 100: HSB (300,68,7) vs. HSB (300,68,100)
    See, that was information that would have been useful for you to share earlier. Using vague colour names and talking about the "frequency" of mauve rendered your argument completely opaque.

    Quote Originally Posted by DaveC426913 View Post
    Let'snot get hung up on the labels. I could have chosen one of dozens of other labels for that colour, or chosen no label at all.
    If all you offer is labels, people will discuss the labels.

    Grant Hutchison
    Last edited by grant hutchison; 2019-Sep-26 at 04:24 PM.

  6. #66
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    Quote Originally Posted by DaveC426913 View Post
    Ay, there's the rub.

    What frequency is the "grey" you refer to? It's not "an equal combination of r g and b", since self-evidently, this does not have an equal combination.
    You can't use the colour "grey" without acknowledging that colour occurs in the brain, not in the light.
    My bold. That is the same fault I found in post #53, using "frequency", singular with no adjective, for light that has to be a mixture of components with different frequencies. If we had a pastel consisting of a mixture of white light with some additional spectral violet, then an expression such as "dominant frequency" or "dominant wavelength" would be fine.

    Gray and white are familiar terms for the sensations we experience with mixtures that are in the same proportions but at different luminance relative to the surroundings. Thus the Moon, if seen alongside snow up close, would appear dark gray, while it appears dazzling white in the night sky.

  7. #67
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    If anyone's interested, there's a pretty good presentation of the concepts of hue, saturation, brightness and lightness here, with a little summary at the end of the difference between HSB and HSL colour spaces. (Personally, HSL makes much more sense to me, but in some applications we're stuck with HSB.)

    Grant Hutchison

  8. #68
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    Thanks Grant.

  9. #69
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    Quote Originally Posted by grant hutchison View Post

    See, that was information that would have been useful for you to share earlier. Using vague colour names and talking about the "frequency" of mauve rendered your argument completely opaque.
    No. It was presumptuous of you to pick a specific set of colour values to define what you consider mauve.


    Quote Originally Posted by grant hutchison View Post
    If all you offer is labels, people will discuss the labels.
    I didn't offer just labels; I also posted a graphic examplar of the thing I was talking about.

    It is not wrong to say "that mauve is the same frequency as that violet". Labels are sufficient.
    It is wrong to say "that is not mauve" without providing more specific criteria. Labels are not sufficient. So such a counter-argument would be hasty.

    Regardless, this is a discussion, so there's some back and forth required, otherwise, we'd have to preface with an entire chapter on colour theory. Let's concentrate on the topic, rather than a peri-mortem meta-discussion.

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    Quote Originally Posted by Hornblower View Post
    My bold. That is the same fault I found in post #53, using "frequency", singular with no adjective, for light that has to be a mixture of components with different frequencies. If we had a pastel consisting of a mixture of white light with some additional spectral violet, then an expression such as "dominant frequency" or "dominant wavelength" would be fine.

    Gray and white are familiar terms for the sensations we experience with mixtures that are in the same proportions but at different luminance relative to the surroundings. Thus the Moon, if seen alongside snow up close, would appear dark gray, while it appears dazzling white in the night sky.
    Right. So, it's pretty much impossible to discuss colour without discussing perception.

  11. #71
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    Quote Originally Posted by plant View Post
    There is no brown in the rainbow.
    Granted, but I'm not really sure what point this makes.

    There is no blue on a pear.

  12. #72
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    Quote Originally Posted by DaveC426913 View Post
    No. It was presumptuous of you to pick a specific set of colour values to define what you consider mauve.
    I actually didn't do any such thing.

    Quote Originally Posted by DaveC426913 View Post
    Let's concentrate on the topic, rather than a peri-mortem meta-discussion.
    Well, all I've been doing is attempting to interpret between yourself and Darrell. I think I've probably finished with that now. (Actually, I'm certain I'm done with it.)

    Grant Hutchison

  13. #73
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    Quote Originally Posted by grant hutchison View Post
    I actually didn't do any such thing.
    ??
    Post 61.

  14. #74
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    Quote Originally Posted by DaveC426913 View Post
    ??
    Post 61.
    That's right.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    If anyone's interested, there's a pretty good presentation of the concepts of hue, saturation, brightness and lightness here,...
    That's a nice one, thanks.

    ... with a little summary at the end of the difference between HSB and HSL colour spaces. (Personally, HSL makes much more sense to me, but in some applications we're stuck with HSB.)
    As the site states, a value (brightness or lightness) of 0 equates to black, and zero doesn't mean "nothing" but a color (pseudo?) the retinex will "see".

    To obtain white, the requirement in the HSB to not only increase brightness but also adjust the saturation level as well is worth noting since, in the HSL system, only lightness requires the adjustment. This seems to be one reasonable argument one might have in favor of the HSL system. Is this a key reason for your favor of it?
    We know time flies, we just can't see its wings.

  16. #76
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    Quote Originally Posted by George View Post
    This seems to be one reasonable argument one might have in favor of the HSL system. Is this a key reason for your favor of it?
    More or less. In terms of colour picking, I find a hue wheel with saturation varying radially and a black-white axis at right angles more intuitive than the HSB/V system. But either system uses black an essential component, which feeds back (at long last) in the OP question.

    For colour matching, I think the CIE colour space becomes intuitive, but only at the expense of some initial hard work to understand what it depicts.

    Grant Hutchison

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    Quote Originally Posted by Strange View Post
    The nearest thing to that is vantablack (https://www.surreynanosystems.com/vantablack). This must exist because it is trademarked and patented.
    There is this: http://www.spacedaily.com/reports/MI..._date_999.html

    I seem to remember reading (Sky & 'scope) that what an object does is reflect the color it..isn't. It is really the color of what it absorbs.--but the author went on to say that something isn't white--or even black..it is BLANK.

  18. #78
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    Quote Originally Posted by publiusr View Post
    There is this: http://www.spacedaily.com/reports/MI..._date_999.html

    I seem to remember reading (Sky & 'scope) that what an object does is reflect the color it..isn't. It is really the color of what it absorbs.--but the author went on to say that something isn't white--or even black..it is BLANK.
    My bold. It is not a matter of what it "really" is. In a thought exercise we can define the color of the object in whichever way is most useful for whatever task is at hand. For most of us that would mean defining it in terms of the reflected light, if any. If it reflects no light it makes perfect practical sense to call it black. I cannot imagine what point that author was trying to make.

  19. #79
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    Quote Originally Posted by Strange View Post
    Reading about that took me to this page on "impossible" colours: https://en.wikipedia.org/wiki/Impossible_color

    There are a couple of examples which combine yellow and blue, or red and green, which seem to cause some people to perceive a colour that is neither and which they cannot describe. When I tried it, I saw a square that had alternating waves of the two colours passing over it. Quite odd.
    I mostly just see fields where one dominates and other fields where the other dominates (when I cross my eyes to look at the blocks of color they provide).

  20. #80
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    Does black exist?

    Yes. Next question.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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    Quote Originally Posted by Noclevername View Post
    Does black exist?

    Yes. Next question.
    Yeah. Didn't work for Samuel Johnson, either.

    Grant Hutchison

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    Quote Originally Posted by grant hutchison View Post
    Yeah. Didn't work for Samuel Johnson, either.

    Grant Hutchison
    But it works for Samuel L. Jackson!
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  23. #83
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    Quote Originally Posted by grant hutchison View Post
    Yeah. Didn't work for Samuel Johnson, either.
    Remarkably, the Wiki on Johnson says that The Oxford Dictionary of National Biography describes Johnson as "arguably the most distinguished man of letters in English history". I did a little spit take on that one, knowing of one other distinguished man of letters who would seem to be overlooked by that claim! Biographers choosing another biographer for that distinction would seem to fall victim of the considerable irony that one of Johnson's important works was "an annotated edition of The Plays of William Shakespeare." Only another literary critic would regard a literary critic as a greater "man of letters" than those who create the literature themselves! (Johnson also created literature, but one can't help note that even though his academic works about literature, and his dictionary, were certainly of huge prominence in academic circles, it is not clear that "distinction" cannot also come from more popular channels!).

  24. #84
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    I think the implication of "man of letters" is not just that you write good stuff, but that you know a lot about good writers and their writing, too.

    Grant Hutchison

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    Also, though it’s a weasel word, he does write “arguably,” which technically means that he is one candidate out of some number of people.


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  26. #86
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    Quote Originally Posted by grant hutchison View Post
    I think the implication of "man of letters" is not just that you write good stuff, but that you know a lot about good writers and their writing, too.
    Precisely the way a critic would define a "man of letters." It would be like historians concluding that the writers of history are the most distinguished "men of history!" (I will grant them that Johnson did create the first major English dictionary, which certainly has a lot of letters in it, so he was quite literally a man of letters-- an impressive accomplishment I must admit. He invented the practice of using quotes from fine literature to underscore the meanings of words-- so his own letters borrowed from Shakespeare and Milton, suggesting that for his own part, he might have regarded them as the "men of letters" of greater distinction than himself.)

    Given all this, one could wonder what Johnson's opinion was about blackness-- he certainly equated an image of a "black dog" with his own death, so perhaps the existence of blackness would be regarded as connected to the existence of the state of being dead? The brain does not say "you're dead, you're dead" like it says "there's no light, there's no light" when you walk into a dark room, but there are some who believe that existence does not require a brain to do anything to establish. As you know, for my own part, I do not hold that there is any existence of "being dead" unless someone else says "he's dead all right," and similarly for the existence of blackness. There's certainly irony there-- I maintain there is not blackness unless someone is either literally there to not see it, or is hypothetically inserted for that same purpose! (If a black tree falls in the woods, is it still black? Only if someone has asserted in some way, real or hypothetical, that they could not have seen it.)
    Last edited by Ken G; 2019-Sep-28 at 06:27 AM.

  27. #87
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    Quote Originally Posted by Ken G View Post
    Precisely the way a critic would define a "man of letters."
    It's just the definition, really. The original meaning was that a person was a scholar - at a time when books were rare and expensive, the "letters" were in things you had read, rather than necessarily in things you wrote. So someone expert in the writings of others. That was the sense in which Johnson was described as a preeminent man of letters in his own time.

    I'm kind of sorry I ever mentioned him, now. My reference was to his famously fallacious argumentum ad lapidem.

    Grant Hutchison

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    Quote Originally Posted by publiusr View Post
    There is this: www.spacedaily.com/reports/MIT_engineers_develop_blackest_black_material_to_d ate_999.html

    I seem to remember reading (Sky & 'scope) that what an object does is reflect the color it..isn't. It is really the color of what it absorbs.--but the author went on to say that something isn't white--or even black..it is BLANK.
    Apart from the point already made (about what the color "really") is, many things have their color for more complex reasons. For example many insects get their color from interference effects created by the surface texture.

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    Quote Originally Posted by Ken G View Post
    Remarkably, the Wiki on Johnson says that The Oxford Dictionary of National Biography describes Johnson as "arguably the most distinguished man of letters in English history".
    It is obviously correct because you are arguing with it!

  30. #90
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    Black in the OP is defined by it's effect on the brain. By that standard, if you can perceive it as black, it's black.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

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