Now I'm finally printing what I was hoping to... thanks to a dichrotic head on a C-700 enlarger. I gave up on my Durst with cold head... as the cold head was the wrong size for the enlarger.

My only problem is that the top of the print is lighter than the rest. It seems to only affect the top 1/5 of the sheet. I'm using the 6X7 mix chamber and a 75mm lens. My negative size is 6X4.5 and 6X6.

The enlarger is second-hand and seems a little loose. I don't know if they come out of allignment and if that could be the cause. If anyone knows of a fix for this problem... please let me know.

christian

-- Christian Behr (info@christianbehr.com), June 06, 2002

Answers

I have a C760 dichroic head. IMO the design is weak, and alignment is difficult. I replaced the plastic buttons on the back of the head with bronze bushings and nylon shoulder washers. I also had to add thin foil shims between the head and the swivel mount (under the lens carrier, where the tilt adjustment is). Those two modifications allow me to adjust the film stage and lensboard parallel. To get the baseboard parallel, I use a 16x20" piece of glass. It sits on top of 4 threaded feet (upside down). Now I can have all 3 planes parallel. I use two mirrors (one has a small hole scratched in the coating) for the barber-shop effect.

After all of that, I don't know if an alignment problem could be causing your problem. On mine (set up for 35mm), I can see the circle of light change as I stop down (no negative). It's nice and round, and very even once I get smaller than f5.6.

-- Dave Mueller (dmueller@bellatlantic.net), June 06, 2002.