Juhani says: October 26, 2015 at three:28 am The condition is usually that you might want to get all the light to 1cm x 1cm space. I've 100W led (8k lm) but I get a lot more light to screen from one 1k lm Cree XM-L2. Next trouble could be the slim wavelength pattern of any led. The colour wheel in DLP projector dimms the light a lot more.I do like