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Thread: Could you make a CYM projector?

  1. #1
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    Default Could you make a CYM projector?

    Just a thought, there is an auction for both a 594nm and a 543nm hene laser on eBay ending in about 4 hours. I don't really hve the $ to spend but it got me thinking. I know 594 is yellow, I would assume 500 even or so would make a good cyan, not sure where magenta would fall frequency wise... if it would fall on a chart. Could you get lasers in all three subtractive colors and make a white projector that way? :? :roll:
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    allthat... aka: aaron@pangolin

  2. #2
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    I'm not sure that approach would work.

    Subtractive colors are used by inks mostly, where color is reproduced by the absorption of the ink of certain wavelengths. If you have cyan, then the ink is absorbing some red, and reflecting green and blue (that is only an aproximation of things, of course). when you have all three colors forming a dot, all colors from light will be absorbed, and you end up with a black dot.

    Additive colors, on the other hand, are, well..., additive. You have green light, and any other color, for that matter. When you combine some colors, let's say green and blue, you end with cyan, which is the combination of both colors, not the absorption. If you combine all three primary colors, you know you end with white.

    On the other hand, magenta is not a color you can find in the visible spectrum, as it's the combination of two colors that are at opposite sides of it (red and blue). So, you can see, if you have a magenta laser, you already have ona laser that can produce red and blue at the same time . Also, color rendition is not only a function of wavelength, but also on intensity (laser power, so to speak).

    As for the combination of all three primary subtractive colors, in additive style, I'm not sure what the result would be, but black it won't be, for sure .

    Does any one around here have a blue (argon or DPSS) and a yellow (HeNe or DPSS) laser that you can combine?, see what color is produced? :P
    Remember the future?, That'd today, as you imagined it yesterday.

  3. #3
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    Quote Originally Posted by jkaiser3000
    Does any one around here have a blue (argon or DPSS) and a yellow (HeNe or DPSS) laser that you can combine?, see what color is produced? :P
    Yep, I can make greenish turquoise depending on the intensities of either laser.
    If I change the Argon 488 out for a DPSS 473 I get better green. still turquiose to me.
    If I lower the blue power I get more green ...cool


    That was a very good explanation of Subtractive and Additive colors.
    At one time I did some study on this., I learned some new things I didnt expect.
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  4. #4
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    There's a pretty good explanation at http://en.wikipedia.org/wiki/Primary_color

    I haven't found anything that really details what colors you could generate though.

  5. #5
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    By marconi's experiences with yellow and cyan, and considering there's no way to produce a magenta laser other than by adding blue and red, then we can conclude that it is, in fact, theoretically possible to produce a laser display with those "subtractive" colors. It would need different handling, for sure. For example, as marconi explained, you'd have to mix the cyan and yellow to produce green. To produce blue, you'd need to blank the cyan and the yellow, and also find a way to uncombine the red from the blue .

    Anyway, this is merely a thought experiment, I don't see any benefit from this as it is more complicated than using plain old RGB, not to mention the magenta laser :P . Maybe the color gamut would be wider?. Who's up for trying?

    Edit: here's a nice applet to show what color is produced with how much of RGB
    Remember the future?, That'd today, as you imagined it yesterday.

  6. #6
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    Jkiaser;

    That's a cool little applet. Thanks for the link!

    Adam

  7. #7
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    As I though about it during the first post I realized magenta would be the kicker. :roll: No million dollar idea here huh... ops: These odd color lasers tend to go for way too much money anyway. The 594nm 10mW hene went for $204. I guess it does have a power supply...

  8. #8
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    It is all to do with the primary colour components.

    In light it is RGB.

    In ink it is RYC.

    Jimbo

  9. #9
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    As jim says ..... on paper its so different...

    I remember reading an artical talking about inks and the colour of the ink pigment absorbs the wanted wavelengths
    and reflects the unwanted wavelengths and it is the unwanted ones that we see ...... so the actual colours of the ink are opersite to what we see

    Now im no expert on this but some one here may be able to shed more info



    all the best and merry Xmas .... Karl

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