Md:

I think we need something more specific. Sunlight is not a unit of measurement so it cannot have a rate. The color of a star is due to a chemical reaction and that will affect how much light is emitted.

If by background one means color of terrain then the rate of sunlight being absorbed (insolation) will vary. White snow covered poles reflect more sunlight and thus would stay cooler than a black aspalted parking lot.

If this doesn't answer the question let me know.
-Rick