Bringing attention to this for science:
>>105555496
>>105555654
You CAN control light sources and darkness in Chroma. The way I've found to accomplish this is by using positional keywords.
>inside a dark lounge. on the left side is a dimly glowing crystal ball on a table, and the left side is dimly lit. on the right side a woman sits in dark shadow in a chair. the right side is dark. the left side of the woman's face is lit by the light from the crystal ball.

Describing the position of things can help tremendously with managing lighting as well as reducing prompt bleed for different characters. Another prompt bleed prevention trick is to keep sentences short. Example:
>Character A has X. Character A has Y. Character A has Z. etc
NOT
>Character A has X, Y, and Z. Character B has E, F, and G