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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
Hello:
Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Is it that the inks are easier to formulate for the subtractive primaries, or ... ? This also seems to be true for the big 4 and 5 color lithographic printing presses. Curious as to why. Thanks, Bob |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
On Wed, 23 Jun 2004 19:49:09 -0400, Robert11 wrote:
Hello: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Dyes subtract. *always*. If your injet was somehow emiting light, it could use additive primary colors. |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y)?
TCS wrote: On Wed, 23 Jun 2004 19:49:09 -0400, Robert11 wrote: Hello: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Dyes subtract. *always*. If your injet was somehow emiting light, it could use additive primary colors. Think we need not the printer to emit light, but rather the photo itself. We need light emitting photo paper Ken |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
In article ,
"Robert11" wrote: Hello: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Is it that the inks are easier to formulate for the subtractive primaries, or ... ? This also seems to be true for the big 4 and 5 color lithographic printing presses. Curious as to why. Thanks, Bob How would you make the color of inks add? Red ink + Green ink + Blue ink isn't white. Some printers do have more than CMYK to improve the gamma, color intensity, or reduce dither intensity. There can also be specialty inks like metallics, ultra-whites, glossy and flat blacks, and fluorescents. |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
On Thu, 24 Jun 2004 00:03:08 GMT, Ken Weitzel
wrote: TCS wrote: On Wed, 23 Jun 2004 19:49:09 -0400, Robert11 wrote: Hello: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Dyes subtract. *always*. If your injet was somehow emiting light, it could use additive primary colors. Think we need not the printer to emit light, but rather the photo itself. We need light emitting photo paper Ken I have a 19" Princeton EO-900 light-emitting paper on my desk. In fact, I'm composing this on it now. :-) Bill Funk Change "g" to "a" |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
On Wed, 23 Jun 2004 19:49:09 -0400, "Robert11"
wrote: Hello: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Is it that the inks are easier to formulate for the subtractive primaries, or ... ? This also seems to be true for the big 4 and 5 color lithographic printing presses. Curious as to why. Thanks, Bob That's a good question! Here's a site with explanation of additive and subtractive colors: http://www.beer.org/~tpark/color.html Bill Funk Change "g" to "a" |
#7
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Is it that the inks are easier to formulate for the subtractive primaries, or ... ? This also seems to be true for the big 4 and 5 color lithographic printing presses. Curious as to why. IIRC, subtractive printing, which nearly all photographic hard copy imagery is based on, uses only enough inks/dyes/pigments required as it goes. Additive printing would require the paper already have the chemistry in it to the max needed and then have the excess removed leaving what is needed behind. this would make papers more expensive. Many years ago, one of the original one hour/small studio machines, the NORD, was additive based. IIRC, the paper was made with dots of the RGB embedded, as they were exposed, then developed the colors would appear, the exposure would make that dot accept or receive the color in development. Its been so long I can remember much. |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
"Robert11" writes:
Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Is it that the inks are easier to formulate for the subtractive primaries, or ... ? This also seems to be true for the big 4 and 5 color lithographic printing presses. It's all in the way that colour is actually controlled. To get a colour space that covers most colours humans can see, you need a technology that can control the intensity of at least 3 colours - usually red, green, and blue. Suppose you have three bright light sources (like slide projectors) aimed at the same spot on the wall. Put a red filter in front of one, a green on the second, and a blue filter on the third. By putting a neutral-density filter or a variable-sized aperture in the optics of each light source, you can regulate the amount of red, green, and blue light reaching the wall. This lets you create almost any colour. This method is called additive colour synthesis, because the three colours follow different paths, are controlled individually, then added together at the end. CRTs create colour this way, as do LCD displays. A few colour enlarger heads work this way too. Now suppose you have just one light source, and only one light path. The only way you can control red independently of green and blue is to use cyan filters. Cyan passes green and blue unaffected, but changing the darkness of the cyan dye controls the amount of red light getting through. Similarly, magenta filters control green without affecting red and blue, and yellow filters control blue without affecting red and green. Each filter passes 2/3 of the spectrum and controls 1/3, so you get independent control of red, green, and blue, even though all the filters are stacked together. This would not work at all for red, green, and blue filters, since they pass only about 1/3 of the spectrum. Red and green filters stacked in sequence produce black, or something close to it, since no light passes freely through both. The control of colour via sequential filters is called subtractive synthesis, because each filter subtracts something from the light. Any image technology that stacks 3 filters in one spot is likely to use cyan/magenta/yellow primaries: inkjet printing, printing presses, colour photographic paper. Most colour enlarger heads use subtractive methods to adjust colour. Dave |
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
Dave,
See TCS's and Ken Weitzel's replies. The answer to the OP's question lies in the difference between emitted light and reflected light. I only direct you to their replies because your reply sounds like you might be a little confused on the matter (even though you have a lot of color theory down)...not to slam you. Have a good weekend, George "Dave Martindale" wrote in message ... "Robert11" writes: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? Is it that the inks are easier to formulate for the subtractive primaries, or ... ? This also seems to be true for the big 4 and 5 color lithographic printing presses. It's all in the way that colour is actually controlled. To get a colour space that covers most colours humans can see, you need a technology that can control the intensity of at least 3 colours - usually red, green, and blue. Suppose you have three bright light sources (like slide projectors) aimed at the same spot on the wall. Put a red filter in front of one, a green on the second, and a blue filter on the third. By putting a neutral-density filter or a variable-sized aperture in the optics of each light source, you can regulate the amount of red, green, and blue light reaching the wall. This lets you create almost any colour. This method is called additive colour synthesis, because the three colours follow different paths, are controlled individually, then added together at the end. CRTs create colour this way, as do LCD displays. A few colour enlarger heads work this way too. Now suppose you have just one light source, and only one light path. The only way you can control red independently of green and blue is to use cyan filters. Cyan passes green and blue unaffected, but changing the darkness of the cyan dye controls the amount of red light getting through. Similarly, magenta filters control green without affecting red and blue, and yellow filters control blue without affecting red and green. Each filter passes 2/3 of the spectrum and controls 1/3, so you get independent control of red, green, and blue, even though all the filters are stacked together. This would not work at all for red, green, and blue filters, since they pass only about 1/3 of the spectrum. Red and green filters stacked in sequence produce black, or something close to it, since no light passes freely through both. The control of colour via sequential filters is called subtractive synthesis, because each filter subtracts something from the light. Any image technology that stacks 3 filters in one spot is likely to use cyan/magenta/yellow primaries: inkjet printing, printing presses, colour photographic paper. Most colour enlarger heads use subtractive methods to adjust colour. Dave |
#10
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Why Do All Printers Use Subtractive Primary Colors (C, M, & Y) ?
"Robert11" wrote in message ... Hello: Anyone have a good technical explanation as to why all printers seem to use subtractive-primary color inks (the Cyan, Magenta, and Yellow) for printing, rather than the additive primary colors of R, G, and B) ? RGB is for things that can generate light (like a TV, monitor, projector etc.) Adding RGB in differing amounts gives a range of perceived colours up to white. The human eye reacts to RGB stimulus. A printed sheet of paper has to rely on reflection of ambient light (illuminant), so all an ink can do is absorb/subtract parts from the original illuminant to reproduce colours. In a nutshell: Cyan subtracts Red Magenta subtracts Green Yellow subtracts Blue So (assuming you are starting with white ambient light), you can reproduce the original RGB values of an image by using varying amounts of CMY inks on the paper. A tad simplified, but hope it helps. |
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