I've been experimenting with this Elwood now for a couple of days and at this po int I wonder what is even illumination on the baseboard? I've tried pieces of gr ound glass, sandblasted a center filter effect on clear glass and a white diffus ion glass. The white glass alone seems best so far. Its still a bit hot in the m iddle - about .5 to .7 stops brighter than the corners. This over an area roughl y equal to a 16X20 using a 4X5 negative. It seems to fall off quite a bit more i n the far reaches - it won't cover 5X7 evenly. So what -is- even enough illumina tion? I'm starting to think that an Aristo cold light head is the real answer. O r a different enlarger. Comments please.