All light emits a specific color wavelength based on temperature in Kelvin degrees.  The Blackbody node provides that temperature range.  For example, candlelight emits a Kelvin temperature of approximately 1500 degrees or a warm color.  Increasing the range to 10,000 degrees or greater provides a bluish tint to the lighting, compatible with a cloudless, blue sky.  In Superfly rendering, the Blackbody node gives you the most realistic, true-to-life lighting especially where PBR is concerned.  In Firefly, you would need to change the color chip to simulate such lighting, unlike in Superfly.  If you animate the Blackbody Node temperature value, you can control it in the Pose Room on the Parameter/Properties panel without entering the Material Room.  Do an internet search and you will find many sites explaining the process and examples.