The Shadow Color is for the Ground Shadows (if enabled) in an UNrendered image.

Try reducing the "Shadow" parameter for your main (sun) light to a lower value,
e.g., 1.000 ---> 0.750.
This will make your shadow a gray value instead of black and may better match you background pic which, if I may, is very nice.

cheers,
dr geep
;=]

Remember ... "With Poser, all things are possible, and poseable!"

cheers,

dr geep ... :o]

edited 10/5/2019