I wrote something a while back about this article. It was mostly about how it is misleading and most of it not really true, the parts that are helpful pertain to mostly uln tanks. The fact they use a green digi as a representative of yellow coral says it all. Not sure what they did to make it look yellow but I know it wasn't what they suggest to do in the article. Probably just camera tricks.
Blue imo will need a good light with the right spectrum. 10k halide bulbs are the best at bringing out solid blues in new growth.