Diffusion vs. Condenser vs. Format vs. Paper

[Nodda Duma]

I even used to live out your way, Drew, when I worked at China Lake.

20% output variance is definitely ok for enlargements.

Barium Sulphate is a good coating and the traditional choice for integrating spheres, but the spectral output will measurably shift as it ages (I believe it's an oxidation issue). Not a problem for an enlarger application, as you can adjust with color filters. Even when the spectral output is critical, the coating can be stripped and reapplied to being the output back into calibration.

That's one of the reasons the industry has shifted to powdered PTFE coating. Ever-so-slightly less output (99.6 vs 99.8 if I remember correctly), but spectrally stable and just as easy to apply.

[Drew Wiley]

Thank you. That particular colorhead is completely unique. It's a V-design with two separate banks of light coming in at 45 deg, with each side requiring its own feedback circuitry, precisely matched to the other. I built it this way to more efficiently cool the two hemispheres. In this respect, it works very well indeed, but is huge and has a lot of finicky circuitry. This was prior to sine-wave control, so taming EMI was quite a chore. It's due for bulb maintenance, so that's when I check the coatings.

[Fred L]

Started off condensers but then began using diffusion. All my enlargers are diffusion now (DeVere's and a Leitz Focomat V35) but still have a Focomat IIc that's condenser. Dust spotting is minimally better with diffusion, but still a chore.

[Luis-F-S]

Started off condensers but then began using diffusion. All my enlargers are diffusion now (DeVere's and a Leitz Focomat V35) but still have a Focomat IIc that's condenser. Dust spotting is minimally better with diffusion, but still a chore.

Ok Fred, you figured it out quickly, not sure why others can't! I also have a Valloy-II but seldom use it! L

[Tin Can]

Anybody notice a clean 4X5 condenser set, only the condenser, sold here for more than a complete enlarger!

Nobody's making them anymore.

[Corran]

Well, you don't have to go pick up the head

I didn't pay much more than that for the 45XL + condenser I bought that started this thread.

[Luis-F-S]

Anybody notice a clean 4X5 condenser set, only the condenser, sold here for more than a complete enlarger!

Nobody's making them anymore.

It was obviously worth it to someone! Nope, they don't make them anymore.

[Gary Beasley]

When I got my first 4x5 enlarger it was missing the condensor set. I got them from Edmund Scientific, now Edmund Optics
https://www.edmundoptics.com/optics/...denser-lenses/
If you can figure the diameter and focal length you can get replacements as long as they are round lenses without cutouts. Even those with edge cutout might be done by cutting with a tile saw.

[Tin Can]

I forgot about Edmonds.

Now we can discuss focal length as Edmonds offers a few!