I take my pics during lights on. If you don't like the yellow of the HPS light then do a custom white balance if your camera has the option. I never use a flash. it's way too intense and makes the photos way too harsh for me.

i like manual settings, here's what i come out with: http://boards.cannabis.com/growing-i...ml#post1928339

Why do you take pictures during lights off? is it the HPS causing problems?

let us know.
Skeet.