I have noticed this: Reflectives work best with bright, white light (say, a Cree LED flood or spot torch); and Fluorescents (as well as "plain" white) work best with a "Black" or UV LED torch - each type glows amazingly well with the proper light shined upon them. White and solid-colour fluorescent nocks (and vanes) also glow almost as if lit from within using the UV LED. The "clear" or translucent-coloured nocks, not so much.
I bought an inexpensive UV LED torch from Mal-Wart, "Rayovac" brand, IIRC. Found it in the camping section with other LED torches - it is anodized a purple colour. It works quite well for arrow-finding in the dark. Thought it might also work well for Blood, disappointingly discovered this is not so. I am still looking for something that will make blood stand out in the dark better than a White Cree LED torch.