Newton's rings on Durst M600 enlargergreenspun.com : LUSENET : Photographers Communicating : One Thread
I have recently started developing B+W prints on a Durst M600 enlarger using Jessops VC filters. I have a glass neg carrier which is not perfect. I have noticed concentric eliptical bandings of shade in mid tones toward the edge of prints. Are these Newton's rings? What causes this and how do I over-come this. At low cost!
-- Ross Jarvis (firstname.lastname@example.org), September 09, 2003
I also use a Durst M600 and yes the problem you have is Newtons Rings.They occur when light is transmitted through two polished surfaces which are in close contact. In this case it is the glossy side of the film and the underside of the condenser which on the M600 clamps the film. It is easy and inexpensive to prevent this by cutting a mask with a 24 x 36 mm hole in itand placing it between the film and condenser . I made mine from thin black card which is excellent as the gap onle needs to be a few thousands of an inch.Durst actually supplied a mask similar to the one I describe ,but I doubt if it is still available as the M600 is now over 20 years old . The M600 is still one of the best enlargers around and far superior to many produced today Regards Neville Cottam
-- Neville Cottam (email@example.com), April 10, 2004.