+1
Most SPS would turn brown with insufficient lighting, especially light loving SPS such as those thick branching acros like staghorns, humillis etc
There are some exception where colors can still be maintain under very low lightings, one classic example would be the radioactive birdnest.
Also, there seems to be a somewhat direct relationship on the nutrient levels vis a vis lighting level that affects the final outcome of SPS color. Simply put it, the higher the nutrient level, the higher amount of lightings is required to retain the color. But this is only true when the nutrient level is not at excessive high level.
Other important factors such as Kh, trace elements, lighting spectrum, flow, Sg level would also play a part in determining the coloration / color intensity of SPS as well. All these factors form a complex inter-relationship that makes up the final outcome. Many good reading materials can be found in the internet with regards to this areas.