Hey, Tom, I keep a spreadsheet with a list of all my orchids and their particular requirements. Since you asked about the lighting for Sobralia callosa (and I was just now updating the spreadsheet anyway), I thought I would check to see what it said. I know this is a pretty crappy definition but honestly, this is the best I could get: "FAIRLY HIGH LIGHT". Don't you hate that when they give those really vague requirements? I would much prefer if they would say "_______ TO ________ FOOTCANDLES" or even "similar to _________". Fairly high light didn't mean anything to me either but right about in the middle of my greenhouse sounded like a "fairly good place". I haven't moved it from that spot since I got it. I suspect it will take more light than what you think as long as you provide lots of humidity and keep it very moist/moderate air circulation. Day temps 72-76, night temps 64-66...too cool & it will not bloom. When I got my space heater, that turned EVERYTHING around. Hope this helps.