I have a Beseler 23CII-dichro. This enlarger is equipped with a fan in the head presumably to keep the bulb cool. I can feel the head vibrating from the fan--it's nota really huge vibration, but certainly noticeable. My question is this: am I losing much sharpness from this vibration? I never see a print in which I think, "gee, that's kind of soft," but I could just not realize how sharp things *could* be. If this is a problem, should I try to disconnect the fan?

Thanks.

-- brad daly (bwdaly@hiwaay.net), May 11, 2000

Answers

Definitely don't disconnect the fan! It's there for a reason. If it's a computer type fan, you can probably get a better one from an electronic distributor. They can also be balanced. If you want to try that, send me an email for more info.

-- Conrad Hoffman (choffman@rpa.net), May 11, 2000.

You'd think that the people designing it would have thought about/tested/proved that the fan was not going to degrade image quality... but you never know!

I know I even stand still and don't touch the bench when enlarging... and wait a few seconds between swinging the red filter out of the light path and pressing the timer button! You just can't be too careful! :)

-- Nigel Smith (nlandgl@eisa.net.au), May 11, 2000.

There could be one of two reasons for the vibration:

1) The fan has aquired a coating of sticky dust that's unbalanced it. Remedy- clean the fan blades.

2) The bearings are shot. Remedy- replace the fan.

Check it doesn't just need a good clean.

-- Pete Andrews (p.l.andrews@bham.ac.uk), May 12, 2000.

Same setup. No such vibration. If you feel it, you can be sure it is affecting your images. Find the problem.

-- Alec (alecj@bellsouth.net), May 13, 2000.

Years ago I had a 23C II and purchased the dichro head with the fan. Beseler boasted how the fan was insulated with rubber bushings, in their literature. There were rubber bushings all right, but the mounting screws ran right through them, thus transmitting the vibration from the fan to the chassis. I could also feel the vibration you mentioned. As far as I was concerned, this was a variable I did not want to enter into my work. I returned the head to the dealer.

-- Jim Billups (jimzpace@yahoo.com), May 14, 2000.

I used to have a beseler MXII 4x5 enlarger with the dichro 45 head which was fan cooled. I wired a switch to the fan. I did all my test prints etcetera with the fan on. Then, when I was ready for the final print, I turned off the fan. I figured 20 seconds or so without fan cooling would not be a problem.

I then did some comparison prints with large enlargements with the fan on and off - and I could not see any difference in sharpness! The lesson: test for sharpness first!

-- Alan Shapiro (ashapiro@yorku.ca), May 18, 2000.