Some ANSI publication on photography? I made some spectral measurements of "daylight" I can share with you, with various instruments, but you have to know that "daylight" is not some absolute, immovable thing. It's very complicated. And probably one of the reason why the CIE has created the "D" series of illuminants. Best / Roger -----Original Message----- From: colorsync-users-bounces+graxx=videotron.ca@lists.apple.com [mailto:colorsync-users-bounces+graxx=videotron.ca@lists.apple.com] On Behalf Of Joseph Chamberlain Sent: Friday, October 18, 2013 10:35 PM To: colorsync-users@lists.apple.com Subject: Help with daylight reference and information. Hi, everyone. I am trying to find the source for the reference below and would appreciate any help you can provide. This is the reference found in a book: “ A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is spectrally balanced throughout the visible spectrum. This light source is defined as equivalent to daylight in Washington D.C. (Bureau of Standards) in the month of June, during the hours or 12:00 noon to 1:00 pm, when there is a slightly overcast sky; the CRI of this light source should be 90 or higher.” Does anyone know the source for this reference ? Also, does anyone know of a chart and/or table with the spectral power distribution of daylight throughout the visible spectrum ? Is there a reference website for this or perhaps a book ? Thank you, Joseph.