This project is still a work in progress, but I think it's come to the point where I can post about it. I have a Beseler 45AF, a somewhat obscure old autofocus enlarger of the Beseler 45 family, and I have a bunch of 5x7 negatives. A couple of years ago, I bought a very old Aristo 5x7 cold light head (the bulb says "Aristo Grid Lite B64" on it, the housing has no markings at all), and my wife has now 3D-printed an extension to mate it to the enlarger, with negative and filter drawers. The distance from the light source to the original negative stage is about 5", which was the minimum we could do that cleared all parts of the enlarger and allowed the corners of the image to clear through the 6.5" holes in the negative stage. There are a couple of fake-leather gaskets where pieces join and where the drawers slot in, to minimize light leakage; they also provide just a touch of additional height, and without them I think the light support would run into part of the enlarger platform.
The attached photos show the anatomy of the whole project: the enlarger foundation after taking the condensers and lamphouse off, the mess of individually printed parts, the assembled extension, and shots of it in place with and without the light, and finally the working enlarger with a 5x7 negative focussed on an 11x14 easel. It's cranked kind of high for a relatively modest enlargement, but there is room to go further; 11x14 is the biggest size I'm set up to print and process, so I'm not worried about that aspect, but someone trying to do a similar project for really big prints would probably want a shorter lens (mine is 210mm).
I haven't actually printed yet, just confirmed that the corners aren't clipped and the image can be brought to focus. The cold light head is heavier than the condensers and lamphouse, and there's some noticeable shift in the platform when I load it up, so alignment will be needed.
Unfortunately this project is a bit specific to the unusual light source; the disc at the top that supports the light would need to be modified for a different head. I think the general design should work for other Beseler 45 models, but I haven't tested it with anything else.
-NT
The attached photos show the anatomy of the whole project: the enlarger foundation after taking the condensers and lamphouse off, the mess of individually printed parts, the assembled extension, and shots of it in place with and without the light, and finally the working enlarger with a 5x7 negative focussed on an 11x14 easel. It's cranked kind of high for a relatively modest enlargement, but there is room to go further; 11x14 is the biggest size I'm set up to print and process, so I'm not worried about that aspect, but someone trying to do a similar project for really big prints would probably want a shorter lens (mine is 210mm).
I haven't actually printed yet, just confirmed that the corners aren't clipped and the image can be brought to focus. The cold light head is heavier than the condensers and lamphouse, and there's some noticeable shift in the platform when I load it up, so alignment will be needed.
Unfortunately this project is a bit specific to the unusual light source; the disc at the top that supports the light would need to be modified for a different head. I think the general design should work for other Beseler 45 models, but I haven't tested it with anything else.
-NT
