I've got a Durst L1200 with a CLS 450 Head - and I've been having the darnedest time controlling the contrast with this enlarger. I routinely find myself having to print at Grade 5 (with fiber, VC paper) in order to get anything approaching blacks and whites. I've never had any luck printing at Grade 3. And even at 5, the contrast in the print seems weak. I've tested my safelight, made sure that I have fresh chemicals (and that the chemicals aren't cold) and VC paper, and I'm using well-exposed negatives. I pulled out my old Saunders LPL6700 and exposed the same 6x6 negative on it - with great results. I bought this L1200 about seven months ago but have just gotten around to using it within the last little while. So - what's up with my L1200 enlarger? Is it possible that the filters in the CLS 450 head are getting old?