Walter, color temperature is simple. If you take a carbon block and apply heat eventually it will glow. When it glows at a certain temperature it's rated at that colour temperature. IE if you heat it up it will go from deep red to red, to orange to yellow and eventually to white and then onto blue. When a bulb says it's a 6500k bulb that's supposed to be what colour the Carbon block would be glowing at that 6500 degrees Kelvin or 6226 degrees Celcius. A 10,000k bulb would give a colour off similar to the carbon block when it's at 10,000 kelvin or 9726 Celcius.
One more thing to help understand the colours is, noon day sunlight at the equator will be between 5000k-6500k depending on the season.
When you get into actinic, you're not talking about a white light so the colour temperature is not applicable, it's a mono chromatic colour, so it's rated at it's peaks.. which should be 430-430nM for actinic.
Doug
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