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From: hildum@iris.ucdavis.edu (Eric Hildum)
Newsgroups: sci.misc
Subject: Re: Color
Message-ID: <685@ucdavis.ucdavis.edu>
Date: Sun, 6-Dec-87 01:00:29 EST
Article-I.D.: ucdavis.685
Posted: Sun Dec  6 01:00:29 1987
Date-Received: Thu, 10-Dec-87 23:31:48 EST
References: <162300002@uiucdcsb>
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Reply-To: hildum@iris.UUCP (Eric Hildum)
Organization: U.C. Davis - College of Engineering
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In article <162300002@uiucdcsb> kadie@uiucdcsb.cs.uiuc.edu writes:
>
>
>I've got two miscellaneous science questions. 
>
>1) On TV's and computers screens, why is it RGB (red, green, blue)
>instead of RYB (red, yellow, blue) the primary colors?

While RYB are commonly called primary colors, there is no real basis
for this distinction. In fact, conceptually, any three distinct colors
could be used for the purpose of creating color images, if we could
subtract light.  In practice, we can only add light sources, thus the
RGB combination is used because it is practical from a cost, benefit,
coverage point of view.  This combination creates one of the larger
gamuts of colors (but not all the chroma that the eye is capable of
perceiving).

>
>2) Some light wave length produces the color green. A mixture of
>the wave lengths of blue and yellow also produces green.
>Even though these two greens are indistinguishable to our eyes, are there
>(could there be) instruments that distinguish them?
>

Yes - but you might want to consider what you mean by "green."  What
is a "green" light? 

The following are a set of references into color vision, the
reporduction of color, and color standards.  If you are interested,
I would suggest that you start with chapter 35 (I think - I am not
certain, but it is somewhere near there) of the Feynman physics text.
It is the most readable of the descriptions of the visual process that
I have found.  I particular, it will answer the question of what is a
"green" light.

@article{kn:faugeras,
	author = "Faugeras, Oliver D.",
	title = "Digital Color Image Processing Within the Framework of a
		 Human Visual Model",
	institution = "IEEE",
	journal = "IEEE Transactions on Acoustics, Speech, and Signal 
		   Processing",
	volume = "ASSP-27",
	number = 4,
	pages = "380--393",
	month = "August",
	year = 1979
	}

@article{kn:horn,
	author = "Horn, Berthold K. P.",
	title = "Exact Reproduction of Colored Images",
	journal = "Computer Vision, Graphics, and Image Processing",
	volume = 26,
	pages = "135--167",
	year = 1984
	}


@article{kn:joblove,
	author = "Joblove, George H. and Greenberg, Donald",
	title = "Color Spaces for Computer Graphics",
	institution = "ACM",          
	journal = "Computer Graphics",
	volume = 12,
	number = 3,
	pages = "20--25",
	month = "August",
	year = 1978
	}

@article{kn:pritchard,
	author = "Pritchard, D. H.",
	title = "{US} Color Television Fundamentals-A Review",
	institution = "IEEE",
	journal = "IEEE Transactions on Consumer Electronics",
	volume = "CE-23",
	pages = "467--478",
	month = "November",
	year = 1977
	}

@article{kn:smith,
	author = "Smith, Alvy Ray",
	title = "Color Gamut Transform Pairs",
	institution = "ACM",
	journal = "Computer Graphics",
	volume = 12,
	number = 3,
	pages = "12--19",
	month = "August",
	year = 1978
	}

@book{kn:boynton,
	author = "Boynton, Robert M.",
	title = "Human Color Vision",
	publisher = "Holt, Rinehart and Winston",
	address = "New York",
	year = 1979
	}

@book{kn:graphics,
	editor = "Beatty, John C. and Booth Kellogg S.",
	title = "Tutorial: Computer Graphics",
	institution = "IEEE Computer Society",
	publisher = "IEEE Computer Society Press",
	address = "Maryland",
	year = 1982,
	edition = 2
	}

*************************************************************
START HERE!!!!!!!!!
@book{kn:feynman,
	author = "Feynman, Richard P. and Leighton, Robert B. and Sands,
		  Matthew",
	title = "The Feynman Lectures on Physics",
	volume = 1,
	publisher = "Addison-Welsey Publishing Company",
	address = "Massachusetts",
	month = "July",
	year = 1964
	}
*************************************************************

@book{kn:foley,
	author = "Foley, J. D. and van Dam, A.",
	title = "Fundamentals of Interactive Computer Graphics",
	publisher = "Addison-Wesley Publishing Company",
	address = "Massachussetts",
	month = "March",
	year = 1983
	}

@book{kn:hunt,
	author = "Hunt, Robert William Gainer",
	title = "The Reproduction of Colour",
	publisher = "John Wiley \& Sons",
	address = "New York",
	year = 1975,
	edition = 3
	}

@book{kn:colortv,
	editor = "Rzeszewski, Ted",
	title = "Color Television",
	institution = "IEEE",
	publisher = "IEEE Press",
	address = "New York",
	year = 1983
	}

@techreport{kn:cie1,
	author = "{CIE International Commission on Illumination}",
	title = "Recommendations on Uniform Color Spaces, Color Difference
		Equations, Psychometric Color Terms",
	institution = "CIE International Commission on Illumination",
	year = 1978
	}

@techreport{kn:cie2,
	author = "{CIE  International Commission on Illumination}",
	title = "Colorimetry-Official Recommendations of the International
		 Commission on Illumination",
	institution = "CIE International Commission on Illumination",
	year = 1971
	}

@techreport{kn:cie3,
	author = "{CIE  International Commission on Illumination}",
	title = "International Lighting Vocabulary",
	institution = "CIE International Commission on Illumination",
	volume = 1,
	year = 1957
	}

>
>Carl Kadie
>UUCP: {ihnp4,pur-ee,convex}!uiucdcs!kadie
>CSNET: kadie@UIUC.CSNET
>ARPA: kadie@M.CS.UIUC.EDU (kadie@UIUC.ARPA)


			Eric Hildum

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