Joe : I used lamps from Duro-Test with a CRI (color rendition index ) of 94. You should look for lamps as close to CRI 100 as possible (CRI 100= sunlight). It should also be noted that lamps lose lumins...See more through use so don't wait for them to burn out, they should be replaced yearly , working or not. Also I was advised not to use diffusers (grills ) of any kind.
Hope this helps.