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color wheel
My Uncle is an artist
I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? -- Dale |
#2
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color wheel
"Dale" wrote in message ... My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? There are others here that can answer you better. As far as I know it is "two rights". RGB is generally in tv, video, photography etc. CMY(K) is usually used in the printing industry. An example is the computer/monitor is RGB, whereas your printer goes by CMYK. Both arrive at the same image though or try to. Tim |
#3
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color wheel
On 12/12/2012 10:31 p.m., Tim Conway wrote:
"Dale" wrote in message ... My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? There are others here that can answer you better. As far as I know it is "two rights". RGB is generally in tv, video, photography etc. CMY(K) is usually used in the printing industry. An example is the computer/monitor is RGB, whereas your printer goes by CMYK. Both arrive at the same image though or try to. Tim Google "additive and subtractive colour". Easy to visualise if you understand that 50:50 red and green pixels on a monitor give you bright yellow, red and green paint (or ink) mixed 50:50 give you a dirty brown, even if dirty brown is just "dark yellow". |
#4
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color wheel
Dale wrote:
My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? An an imaging system engineer, you'll already be aware of the differences between additive and subtractive colours, so that can't be the difference you're looking for. What colour wheel is your uncle using? Does it have a name? BugBear |
#5
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color wheel
On Wed, 12 Dec 2012 03:15:14 -0500, Dale wrote:
My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? http://en.wikipedia.org/wiki/Complementary_colors indicates that it depends on what your primary colors are - the complement of a color is obtained by mixing equal portions of the other two primaries. |
#6
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color wheel
On 12.12.2012 09:15, Dale wrote:
My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? All wrong. First of all, RGB is not a color system. There isn't "one RGB", there is at best a color gamut, and RGB are three primaries picked arbitrary within the gamut. However, that's a subset of all available colors, namely everything within the RGB triangle. A popular choice for primaries are of course red, green and blue, but do not need to be. Any three linearly independent colors do. Thus, *a* RGB color space (not *the*...) is the triangle in the XYZ color gamut spawned by three primaries. These may or may not be red, green and blue. Second, CMY (or CMYK) is often referred to as "subtractive" color format, though this is highly misleading. I would rather call this a multiplicative color space. In RGB, the output color is generated by additive mixture (overlay) of colors. In CMY, a white color input undergoes filtering by three spectral filters. Thus, a C (cyan) filter would remove red. This is multiplicative because the filter characteristic of applying two filters (such as C and M) is a filter whose spectral sensitivity is the pointwise product of the C and M filter. As for RGB, which primaries you pick is entirely up to you. There is no need for them to be C, M and Y, though this a popular choice. CMY models the color reproduction in print - color pigments act as filters, RGB the color reproduction of displays, where light mixes. |
#7
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color wheel
Dale wrote:
My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB What are these "other complements or opposites to RGB"? I have a friend who is a photographer. He was taught, and always refers to, Blue, Red, Yellow filters on his colour enlarger but, when I looked, these were simply unusual names for Cyan, Magenta, Yellow. does anyone know why this situation is? are there two rights or is someone wrong? What you describe is really two *wrongs*, as human perception uses something close to Lab. -- Regards, Martin Leese E-mail: LID Web: http://members.tripod.com/martin_leese/ |
#8
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color wheel
In article , Dale wrote: My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB In printing, that is definately true--cyan is the absence of red, magenta is the absence of green, and yellow is the absence of blue. he and apparently many others use a color wheel where the are other complements or opposites to RGB http://en.wikipedia.org/wiki/RYB_color_model Artists tend to think of red, yellow and blue as the primary colors. And, for some reason, this system works when you are mixing paints. Red and yellow give you orange, yellow and blue give you green, and red and blue give you purple. Three primaries + three secondaries give you six basic colors, seen on the pride flag, most non-technical color wheels, and cartoon depictions of rainbows. Personally, I find the artist's color wheel with red, yellow and blue equally spaced more aesthetically pleasing than the RGB color wheel. Anyway, on the artist's color wheel, the complimentary pairs are red-green, yellow-purple, and blue-orange. does anyone know why this situation is? are there two rights or is someone wrong? Artists came up with this color system long before the physics of color vision were understood, so it is not surprising that they identified a different set of primaries. I wouldn't call it "wrong", either. To me, green "looks like" a mixture of blue and yellow, while yellow does *not* "look like" a mixture of red and green. Of course, this could be a cultural bias implanted back in pre-school, I don't know. -- "Remember when teachers, public employees, Planned Parenthood, NPR and PBS crashed the stock market, wiped out half of our 401Ks, took trillions in TARP money, spilled oil in the Gulf of Mexico, gave themselves billions in bonuses, and paid no taxes? Yeah, me neither." |
#9
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color wheel
On 12/12/2012 12:47 PM, Thomas Richter wrote:
On 12.12.2012 09:15, Dale wrote: My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB he and apparently many others use a color wheel where the are other complements or opposites to RGB does anyone know why this situation is? are there two rights or is someone wrong? All wrong. First of all, RGB is not a color system. There isn't "one RGB", there is at best a color gamut, and RGB are three primaries picked arbitrary within the gamut. However, that's a subset of all available colors, namely everything within the RGB triangle. A popular choice for primaries are of course red, green and blue, but do not need to be. Any three linearly independent colors do. Thus, *a* RGB color space (not *the*...) is the triangle in the XYZ color gamut spawned by three primaries. These may or may not be red, green and blue. Second, CMY (or CMYK) is often referred to as "subtractive" color format, though this is highly misleading. I would rather call this a multiplicative color space. In RGB, the output color is generated by additive mixture (overlay) of colors. In CMY, a white color input undergoes filtering by three spectral filters. Thus, a C (cyan) filter would remove red. This is multiplicative because the filter characteristic of applying two filters (such as C and M) is a filter whose spectral sensitivity is the pointwise product of the C and M filter. As for RGB, which primaries you pick is entirely up to you. There is no need for them to be C, M and Y, though this a popular choice. CMY models the color reproduction in print - color pigments act as filters, RGB the color reproduction of displays, where light mixes. yeah I forget, there is no one RGB or CMY -- Dale |
#10
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color wheel
On 12/12/2012 06:45 PM, Paul Ciszek wrote:
In article , Dale wrote: My Uncle is an artist I have ten years work experience as an imaging system engineer I was always under the impression that CMY were the color complements or opposites of RGB In printing, that is definately true--cyan is the absence of red, magenta is the absence of green, and yellow is the absence of blue. he and apparently many others use a color wheel where the are other complements or opposites to RGB http://en.wikipedia.org/wiki/RYB_color_model Artists tend to think of red, yellow and blue as the primary colors. And, for some reason, this system works when you are mixing paints. Red and yellow give you orange, yellow and blue give you green, and red and blue give you purple. Three primaries + three secondaries give you six basic colors, seen on the pride flag, most non-technical color wheels, and cartoon depictions of rainbows. Personally, I find the artist's color wheel with red, yellow and blue equally spaced more aesthetically pleasing than the RGB color wheel. Anyway, on the artist's color wheel, the complimentary pairs are red-green, yellow-purple, and blue-orange. does anyone know why this situation is? are there two rights or is someone wrong? Artists came up with this color system long before the physics of color vision were understood, so it is not surprising that they identified a different set of primaries. I wouldn't call it "wrong", either. To me, green "looks like" a mixture of blue and yellow, while yellow does *not* "look like" a mixture of red and green. Of course, this could be a cultural bias implanted back in pre-school, I don't know. thanks -- Dale |
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