Can anybody tell me a bit more about Luminol?

Question

I just want to make sure about the results on Luminol, after blood has been cleaned and a layer of paint applied, will investigators still be able to detect blood with Luminol?

Answer 1

I am going to assume you are trying to check the quality of the research done for your latest CSI show, and yes it is possible for trace amounts to remain even in the scenario that you suggested.  It takes only a very minuscule amount of blood to react and when two liquids blood and wet paint actually mixes and it still reacts with luminol.