Path: utzoo!mnetor!uunet!husc6!rutgers!lll-lcc!well!wcalvin From: wcalvin@well.UUCP (William Calvin) Newsgroups: sci.misc Subject: Re: Color Message-ID: <4673@well.UUCP> Date: 9 Dec 87 07:51:20 GMT References: <8VicPfy00Xo3QHM08t@andrew.cmu.edu> Reply-To: wcalvin@well.UUCP (William Calvin) Organization: Whole Earth 'Lectronic Link, Sausalito, CA Lines: 12 Color hues are basically a function of the relative activity in two cone types, e.g., the ratio of "red" cone to "green" cone activity gives yellows whether it is accomplished by a 540 nm pure wavelength or a mixture of 500 and 600. But red and blue cone absorbance curves don't overlap enough so as to produce some ratios with any single wavelength stimulus. The ratios produced by a 400 and 700 nm mixture are not unique but they cannot be matched by a single wavelength. We call it purple. William H. Calvin University of Washington NJ-15, Seattle WA 98195 wcalvin@well.uucp 206/328-1192