Fired up my homebuilt enlarger!

[Rafael Garcia]

"Finished" my 5x7 homebuilt enlarger and ran some test enlargements today. Fantastic! Here are some pics:



The enlarger has a cold head - an array of six under counter fluorescents. I am working on a condensing head also. Focusing is difficult in extreme enlargements because the focusing knob ends up beyond reach if looking at the image closely...other than motorizing, an extension to the focusing knob is the only other way I see around that.

[David A. Goldfarb]

Very interesting approach. I like it.

[Nick_3536]

Cool idea using the shelfing racks for a vertical. Personally I'm leaning towards a horizontal.

[Frank Petronio]

What's the total investment? Looks like a nice do-able solution.

[Jimi]

Really good idea with the shelving racks. The results from it looks promising too. Might come in handy some day. Thanks for sharing.

[GPS]

Aren't the shelving racks the week point of the construction? They are quite freely attached to the wall rack and if touched they can easily change the parallelisme of both the paper table and the magnifying head.

[Rafael Garcia]

Thanks for the comments. The support system worried me the most in planning it, as it had the potential to be a massive engineering project. I settled on the shelving system after considering complicated tracks with pulleys, etc. It made sense because it was cheap, pre-engineered to be solid, and, because both the head and the paper platform are bolted to the brackets, very rigid. The fact that the distance between head and platform is in fixed increments can be overcome by using a few books to shim the easel up if needed.

Loss of parallelism is not an issue with the shelf racks. The wall is solid concrete (basement wall) and the shelving system is heavy duty. The brackets don't sag. Parallelism plays a part in the focusing system, though, and I'm still working on it: the front two carriage bolts bind a bit when focusing, which means the platform is not always parallel to the lensboard. I am considering removing the carriage bolt system and replacing it with ball bearing drawer hangers. The other issue I find is that, when I lower the platform for large enlargements, the focusing knob is out of reach. I may have to make an extension to help with this.

Total investment is hard to determine, since I used a lot of stuff I had around, including most of the wood. The other parts include:

a) Shelf brackets and standards - around $20.00
b) Under-counter fluorescents - around $ 50.00
c) Threaded rod, carriage bolts, knob, aluminum bar stock - maybe $30.00
would cover it
d) Vinyl blackout shade (the bellows are four sections of shade taped with gaffers
tape and then covered in left-over fabric from my focusing cloth) - $2.00
e) Sheet of 2x2 fluorescent light diffusser (used a piece below the fluorescents to
diffuse the light). - $2.00 maybe
f) 210mm Schneider Componon 5 x 7 enlarging lens - eBay for $50.00 (lucky day)
g) negative carrier made out of two cheap 5x7 picture frames - $4.50

In total, including optics, around $200.00 to 250.00 .

I have bought a 7 1/2" (180mm) and a 165mm lenses on eBay also, which will reduce the length the focus so I can enlarge less! My objective is to make 8x10s from my 5x7 negatives, and ocassionally blow up parts of the negatives more, or larger.

[David A. Goldfarb]

I think you'll find that the fluorescent lamps have a ramp up time, which will make short exposures inconsistent. You'll notice it the first time you try to print a series of identical prints from the same neg.

You might want to add something like a Packard shutter, so you can leave the lamp on and open the shutter for focusing or the exposure. A more expensive option would be a Metrolux timer, which should give very consistent results.

[Rafael Garcia]

Thanks for the comment. I had read something about that... food for thought. I am working on adapting an Omega D-2 head I have around to it, so I can have condensing power. That can also help with the issue.

Meanwhile, I am posting a better example of the enlargement capability (I got lazy with my scanning when I posted the original photos, and picked an enlargement that was not as sharp). This was actually the first photo enlarged with it:

[Nick_3536]

Six bulbs? How much total wattage? How long are average exposures?