Beseler 23C evennesss-of-illumination problem

[peter_hughes]

I have a Beseler 23C Dual Dichro enlarger which I have setup in diffusion mode: with the hex-cell diffuser and diffusion chamber. I am having an exasperating problem with uneven illumination; i.e., a center hot spot that is quite noticable on the final print. I am using Schneider Componon-S lenses. I have tried the following, to no avail:

 

1.Switching the lamphouse to a standard enlarging bulb.

 

2.Replacing and/or augmenting the diffusion discs.

 

3.Aligning the enlarger.

 

I have checked everything I can think of. I am a very experienced worker--35 years in the photo field--and have never come across anything like this. Right now, I have to edge burn about 1/2 stop to compensate.

 

Can anyone help?

[lightcraftsman]

What specific lens are you using? I have found a 105mm lens works fine for 6x7 prints. Are you using the 6x7 mixing chamber? Are you printing color or black and white? I have successfully used an Aristo cold light head for black and white on this enlarger, but of course that would not work for color.

 

<p>

 

If you are using a 105mm lens stopped down to at least f/8 and projecting through the 6x7 mixing chamber, I would suspect a problem with the print head. Maybe a longer lens would help?

[steve_bingham]

The problem probably lies with your lens. Even though you MIGHT be able to get a 60mm lens to give you the coverage, it won't be even. Also, some 90mm lens won't give you proper coverage. They can vary a great deal. Darron gave you a good answer. I never had any problems with this set up YEARS ago. I beleive I was using a 105mm. You didn't say what lens you were using so all this is pure speculation.

 

<p>

 

Steve

[bill_lawlor]

Peter, I had the same problem with the 23 and Dual Dichro. After trying all the same fixes I decided the design is flawed. All other color heads with diffusion chambers direct the light into a chamber where it bounces around and exits the side nicely mixed. The 23 DD head directs the light directly down onto the neg through a diffusion cone which is never right. I got all kinds of density do-nut rings in 11X14 color prints. I finally got rid of the whole thing and got a used Chromega 67 setup which was far superior in every way to the 23. I would still be using it today if somebody had not given me a Beseler 45. I sold the Chromega to pay for a 45S color head in which Beseler did it right by directing the light into the side of the mixing chamber and out the bottom. Also, the 23 DD has problems with the power supply and regulation. In condenser mode the original 23 is a good b$w enlarger but the DD head is a fraud. They don't make it anymore. I highly recomment the Omega 67 with Chromega colorhead.

[al_sapouckey1]

I have a question about Bill Lawlor's answer to this question. He say's that Beseler doesn't make the DD head any more. Does that mean that the 23CIII-XL Diffusion Dichro Enlarger listed in ADORAMAs 1997 catalog is a different design and not subject to this illumination problem? I'm looking for a medium format enlarger that will do 6 X 9 and there doesn't seem to be very many choices out there if you want to avoid the expense of a 4 X 5.

[steve_g]

I HAVE USED THE 23C11 DD ALSO & HAVE FOUND THAT THE HEADS HITS THE FRAME AT 2 SPOTS. REVERSING THE BRACKETS SEEMED TO HELP.

ALSO WHAT BULB ARE YOU USING?

[ron_musick]

I've ran across this problem also. Just lower the Condenser stage to the lowest setting (2 1/4 X 3 1/4). This should produce the result you're looking for.

 

Hope this helps.