Expressed in Lumens, it is the time rate of the flow of Light.
Radiant energy in the visible region of the spectrum, varies in its ability to produce visual sensation; the variation depending on the wavelength.
Simply, some colors appear "brighter" than others.
The ratio of the luminous flux to the corresponding radiant flux is the Luminosity Factor, or Visibility Factor - and is expressed in Lumens Per Watt. This varies with wavelength, having a maximum at approximately 5,550 Angstroms.
In a nutshell, the topic is referring to the color tones which comprise White Light - either as individual, stand-alone colors, as "mixed" combinations of colors, or all colors combined - as in White Light.
Sound kind of right? Also, does this make sense and/or appear to be what you are looking for as a description?
Scott " 35 " Thompson Just Say NO To Green Eggs And Ham!
Yes Scott, that explained it perfectly mate!. I haven't heard the Angstrom used in a few years. But I remember it being used when I was an Apprentice Liney, we were talking about Street-Lighting and the lack of colour-rendering that Sodium Lighting has. Is the CRI used in the US?.
Let's face it, these days if you're not young, you're old - Red Green