I have being using a Durst M670 BW for several years but have recently encountered a fogging problem with the enlarging lens.
1. I insert my neg and turn on the enlarger and compose my image.
2. When satisfied I turn it off and get a test strip and put it into position.
3. I set my f stop timer for test strips.
4. I switch on to start the sequence only to discover that the lens has misted over. It is the upper glass element nearest the neg. that has fogged over. This requires me to remove it and dry it off.
I have being using this lens and enlarger for several years with out encountering this problem.
Any ideas or suggestions ?