From rvenable@deimos.cber.nih.gov Sat Aug 16 23:18:06 1997 Received: from deimos.cber.nih.gov for rvenable@deimos.cber.nih.gov by www.ccl.net (8.8.3/950822.1) id XAA14240; Sat, 16 Aug 1997 23:07:42 -0400 (EDT) Received: from localhost by deimos.cber.nih.gov with SMTP (1.37.109.14/16.2) id AA161307073; Sat, 16 Aug 1997 23:04:33 -0400 Date: Sat, 16 Aug 1997 23:04:33 -0400 (EDT) From: Rick Venable To: chemistry@www.ccl.net Subject: color to greyscale Message-Id: Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Someone recently asked about converting color to greyscale; I came across the following in graphics FAQ file somewhere: Q: How do I convert color to grayscale? A: The NTSC formula is: luminosity = 0.299 red + 0.587 green + 0.114 blue NTSC is a convention for television signals (in North America), so the above is how a b&w TV should display a color broadcast. The resulting luminosity will be over the same range as the red, green, and blue values, typically 0..1 or 0..255 For an existing image file of some sort (PostScript or other format), there's a fair number of freeware tools which can be used to convert to greyscale; I use ghostscript, xv, and the netpbm suite a lot on Unix systems. A good information source for X windows freeware is http://www.ee.ryerson.ca:8080/~elf/xapps/faq.html -- Rick Venable =====\ |=| "Eschew Obfuscation" FDA/CBER Biophysics Lab |____/ |=| Bethesda, MD U.S.A. | \ / |=| ( Not an official statement or rvenable@deimos.cber.nih.gov | \ / |=| position of the FDA; for that, http://nmr1.cber.nih.gov/ \/ |=| see http://www.fda.gov )