Vignetting help with Beseler 23c Series II

[RJMLuke]

I recently bought a Beseler 23c enlarger with a Schneider 2.8 lens. I know this is a quality enlarger and am wondering why I have this problem with vignetting. Any time I print a full frame, the corners are lighter than the center. Almost like an enlarger hot spot. From other discussion boards, I read that the problem could be the position of the condensers which can be solved by turning the knob which elevates the unit. I try to align the arrow on the negative size indicator to 8mm, 16mm, 35mm...but at this height, the unit is no longer supported by the metal back. Any advice on how to set this enlarger to print evenly lit 35mm and smaller negatives? Thank you very much. Will post results when solved.

best,
-R

 

[Venchka]

Sorry. You are using 35mm film. I never had any trouble with mine. The condensors worked for 35mm & 6x7. Something doesn't sound right with the track for the condensors. Unfortunately I don't have that enlarger anymore.

 

[ricksplace]

I don't understand what you mean by ...but at this height, the unit is no longer supported by the metal back."

I have a 23C that I use extensively. I never have any trouble with vignetting unless I forget to set the condensor height. Incidentally, the settings on the enlarger for height of the condensors labelled as 35mm, 6X6 and 4X5 really pertain to the enlarging lens you use. For example, if you use a Componon 80/5.6 for enlarging 35mm negatives, you should set the condensor height to 6X6. It's a great enlarger. Built like a tank.

 

[Venchka]

I It's a great enlarger. Built like a tank.

That was my impression too. Sorry I sold mine.

 

[ic-racer]

Do you have this?

http://www.darkroompro.com/pdf/enlargers/beseler_23c1.pdf

 

[ic-racer]

Check out the picture on page 8. Does yours look like that? Or is something missing or broken?

 

[Nicholas Lindan]

I try to align the arrow on the negative size indicator to 8mm, 16mm, 35mm...but at this height, the unit is no longer supported by the metal back.

I think your enlarger is missing the little metal arrow that points to the condenser positioning scale - as ic suggested, see page 8 of the manual. If you raised (tried to raise) the head so the bed of the condenser assembly is at the "35mm" mark then vignetting is what should get.

For some reason the arrows and the condenser positioning scale are the first bits to fall off of a Beseler.

 

[smieglitz]

If you have an under-the-lens filter holder, check that as well. Sometimes they get in the light path and are not noticed.

You also don't mention the focal length of the lens you are using. 40mm is the shortest I've ever seen used on one of these enlargers. If you have a 50mm lens, the condenser assembly should be racked all the way to the top. A 100mm lens will have it all the way to the bottom, and 75mm or 80mm will be towards the bottom end.

 

[dancqu]

Check out the picture on page 8. Does yours look like that?
Or is something missing or broken?

Page 8. There it is mentioned that any size negative
may be used which is within the range set. So, with the
condensers set for 21/4 x 31/4 that size and any smaller
negative will receive even illumination. As well, with the
condensers set so any focal length lens up to maximum
may be used.

With Beseler enlargers the higher the condensers are
above the negative stage the more condensed narrowly
focused is the beam of light at the negative stage. With
Omegas condensers are individually repositioned or
supplementary condensers are added.

Some enlargers have NO provision for condenser
adjustment. They are set to cover the rated size
negative and so any size smaller.

Condenser adjustments are an Extra. Dan

 

[Saganich]

Is the correct bulb in there?

 

[Smudger]

a poster on PhotoNet (?) described a problem similar to yours which he claimed to have eliminated by painting the assembly around and behind the bulb white.
(-it comes in matt black from the manufacturer )
May be worth a try.