Juhani suggests: Oct 26, 2015 at 3:28 am The challenge is always that you'll want to get all the light to 1cm x 1cm area. I've 100W led (8k lm) but I get extra light to display screen from solitary 1k lm Cree XM-L2. Second challenge is the narrow wavelength sample of any led. The colour wheel in DLP projector dimms the light even more.From the lamp