Thanks so much for this. I adore the lighting on Merlin which adds so much to the look of the show, but had no idea how the effects were achieved. You wrote a wonderfully clear explanation here.

Sorry you're still unwell. Hope you feel better soon ♥

P.S. I went to Warwick Castle recently and wrote about it in my LJ here. I don't know if it counts as a Merlin location but if it does I could either link to my post or repost it here if you'd like?