I recently aquired a Durst Laborator G 139 enlarger with 5 condensors: 2 x 240, 240H, 200, 160. I'd like to use my Schneider enlarger lenses for the three formats I use: 5.6/180 Componon for 13x18 (5x7"), 5.6/135 Componon-S for 4x5" and 5.6/100 Componon-S for 6x7. I got a copy of the original handbook for the enlarger, but one thing irritates me: which condensor is the correct one for which lens and format. In the handbook are tables for Componon and Rodagon lenses, and the condensor values are different for the same focal length. I tried both (e.g the one for the 135 Componon [240/160] and the 135 Rodagon [240H/200] with 4x5) and both combinations were different, but not very good. I got very uneven illumination (up to 1.5 stops from center to the edges of the negative). I haven't moved the bulb yet.

Has anyone experiences with this problem? How critical is the adjustment of the bulb?

Martin

-- Martin Jangowski (Martin@Jangowski.de), January 26, 2000

Answers

I have the L138S, but I don't know how similar it is to the 139. An almost identical model was made with a point source lamp for electron microscopy negatives, but I forget the model number. On my 138S enlarger, it's simple: There is a big chart printed right on the lamp housing that lists recommended enlarging lens/condenser lens combinations (along with direction of insertion of the condensers) for every format from 35mm to 5X7. Are you sure sombody didn't remove the metal plate with the chart printed on it from the lamp housing? It should be right on the front on the slanted part of the housing where the mirror is located.

As for bulb alignment, yes, it does matter. I simply adjust it by eye for the most even illumination I can get. There might be a more sophisticated way of doing it, but that's what works for me. There are several types of bulbs you can use as well (also printed on the metal plate on the lamp housing).

-- Bill Riemenschneider (willir@hotmail.com), January 26, 2000.

I bought a Durst 1200 with condensor head (I know, it's not the same model you have, but I think it's still relevant). I couldn't believe how uneven the illumination was, no matter what I tried alignmentwise, bulbwise, or otherwise (I even tried putting all sorts of diffusion material between the condensors and the negative, to no avail; still a major hot spot, with a couple of stops loss toward the edges). After asking everyone I could think of, I finally just gave up and bought the Multigraph head, which put me into serious hock but is the best light source imaginable on the best chassis around. Re: your situation, I would contact Durst (though their customer service has a bad reputation in this country, they've got a field rep somewhere in PA--sorry, I've lost his name--who knows more than their h.q. does; they'll give you his name) and/or the photographer/writer Joe Englander, who raved so much about Durst enlargers that he persuaded me to buy one. (Btw, the light bulb assembly in my 1200's expensive condensor head was mostly flimsy plastic; it looked like it cost about 7 or 8 bucks to make).

-- Simon (fourthpres@aol.com), January 26, 2000.