Yesterday I tried to test my Durst M 600 with a 35mm negative to enlarge of size 20x25cm.
Enlarging lens: Schneider Kreuznach @f/8 50mm.
Paper: MCP 312
Without filter: Paper speed is ISO 400 require 20.2 sec(f-stop printing).
With Grade 3 filter: Paper speed is ISO 160 require 64 sec(approximately).
Paper: Adox Vario Classic
With Grade 3 filter: Paper speed is ISO 40 require 256 sec(approximately).
Filter was placed under the lens.
Paper Developer: ECO 4812 Moersch.
Question: Is it normal to have such a long exposure times for paper.