Hi again, everyone. I have done quite a bit of research but haven't found the answer to two questions. Any help or guidance you can provide will be very appreciated. Here they are: 1. A textbook with a chapter on color theory (the book itself is not about color technology) has a reference for daylight but I haven't been able to find the source for this reference. Here it is: " A full-spectrum light source, as recommended, is one with a color temperature close to 5500 K (D55) that is specifically 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 of 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. " Do any of you know the source for this reference ? 2. I have been trying to understand the difference between a color model and a color space but haven't found any text or any source that provides a good definition for either one or explains both in a manner that is clear and simple to understand. I am trying to understand the following: 2.a. Is Lab a color model or a color space ? 2.b. Is the Munsell Color system a color model ? In this case is the Lab a color space based on the Munsell color system (color model) ? 2.c. Is RGB a color space ? 2.d. How can I draw graphs comparing the color spaces defined by RGB, Adobe RGB and ProColor ? In case I have a raw file created by a 12-bit and another created by a 14-bit camera, how can I draw a graph depicting the difference in the color spaces of these two cameras ? Thank you again in advance for your help. Joseph.