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.