I haven't used graded papers in years, but back when I did I used a standard Aristo coldlight head for those papers. For nearly 20 years I've printed on VC papers using an Aristo CL4500 head. This is a cold-cathode V54 tube (specifically made for VC papers, according to Aristo back in the day) with a filter drawer immediately under the light source.Are you using fixed contrast papers with your cold-cathode head Alan?
I have both condenser and diffuser types in my Darkroom. My 35mm model is the Leitz V35 which is essentially a diffuser, but also incorporates a condenser element. For 120 I use a Durst M601 in its condenser arrangement. I have an LPL 7451 for 4x5 which is a straight diffuser with a colour head. I don’t notice any significant difference with regard to dust or scratches between them. Clean, undamaged negatives are the way forward (not that mine always fit that description). The Durst doesn’t produce a startling difference in contrast from the other two. I don’t alter development to suit each enlarger, but simply adjust contrast filtration on the enlarger. There is rarely a difference of more than a half to one grade, which is well within the scope of filtration (or most graded papers).I have read that condenser enlargers are prone to show more dust. Have you experienced this
David,We forgot to mention the ultimate condenser machine – the point source enlarger. Not a practical proposition for printing images, but it's example of the extreme limit of available devices. I found I preferred a diffusion source, but I'd also switched from an anonymous crackle-finish machine with a pantograph (and alleged auto-focus) to a De Vere, so having an enlarger that I really liked may have influenced me. Once you've experienced the waist level wheels, you never want to go back.
Surely the only change needed is to add a half minute, or whatever, to development times? I don't doubt that martin-f5 gets the strong blacks that he likes but I don't quite understand the mechanics of it.