I would consider a cold light source. I have the Aristo T-12, which is a 12x12 unit which has a V-54 tube and is rated at 320 watts, and it is more than adequate for 8x10. Aristo also makes a T-28, which is a 24x28 inch model with 1070 watts, and a T-36, which is a 32x36 inch model with 2140 watts. I’ve talked to the engineer at Aristo, and as I understand it, Aristo can bend up a V-54 tube for these, and possibly supply a higher voltage transformer to even more light output.