Has anyone used a dimmer control on their Beseler enlarge to decrease the light output, and increase exposure times? if so, how well did it work for you?

-- Jim B. (jimzspace@yahoo.com), June 14, 2000

Answers

Yes. I am using a light dimmer on my enlarger. It cost me about $30 at the local hardware store. I've read that using a Variac is the best way to go because it protects you from ups and downs in current output, but I've never experienced any problems with a plain old dimmer. (And frankly, at this time I can't afford to buy a Variac.) Anyway, I found that using a dimmer does definitely help, since it gives me more time to work at 5.6 and 8 and it also gives me more time to dodge and burn. Further, it should help extend the life of your enlarger bulb. BTW you can find an article on this subject in the latest edition of Phototechniques.

-- Christopher Hargens (ldmr@cruzio.com), June 14, 2000.

The thing about Variacs protecting against voltage variation is a fallacy. People confuse them with constant voltage transformers, which are a different beast altogether. A Variac is simply an auto-transformer with a continuously variable tapping. The tapped voltage will go up and down with the input voltage as well. You can servo a variac with a motor and feedback system to get a constant output, but it's a rather old-fashioned and cumbersome way of doing it.

Variacs usually allow a 20% increase in voltage as well as a decrease. For dimming purposes only, cheap dimmer-switches are as good as anything.

Please, please, be careful with home-made electrical apparatus, especially in the darkroom. Don't ever be tempted to try out a "lash up". Build it into a purpose made box, and get someone in the trade to check it for you before you use it.

We've all heard stories of uncle Joe, who sticks his fingers in the light socket to test for the "juice", and it never hurt him, (and he smokes 60 a day, and drinks like a fish, blah, blah, blah). Well uncle Joe (1)is very lucky, (2)has skin like old leather, and (3)is probably already clinically brain-dead anyway.

Good luck, but be careful.

-- Pete Andrews (p.l.andrews@bham.ac.uk), June 15, 2000.

I bought my Beseler 45 outfit as a piece from a friend, and it came with a Zone VI Cold Light Stabilizer which has a lamp intensity dial on it. I have found this very useful for both lengthening and shortening exposures. I'm sure it's not cheap, but it also has a handy dial for reducing lamp output by percentages to adjust for print dry-down.

-- Ed Buffaloe (edbuffaloe@unblinkingeye.com), June 15, 2000.

As a matter of curiosity: I know that changing the voltage at the lamp will change the spectrum of the light that is emitted. (Lower voltage means more red light.) This could change the apparent sensitivity of the paper as well as the grades of VC papers. Has anyone found this to be a problem?

-- Thomas Wollstein (thomas_wollstein@web.de), June 15, 2000.

A light dimmer will definitely work in this application, but they have an annoying problem with hysterisis. What happens is that whenever a bit of noise or voltage change occurs on the line, they can change their setting to a new value. In a choice between a dimmer and a Variac, I'd choose the Variac, but in a choice between a dimmer and nothing, I'd go for the dimmer every time! Reducing the voltage by either method for reasonable amounts doesn't seem to change the paper grade (on VC papers) by much at all (less than half a grade). Also, never use the overvoltage tap on a Variac, as the bulb life will be reduced drastically. There's always a tap for 1:1 ratio. Variacs (and other autotransformers) don't regulate at all. You need a CV (constant voltage) transformer like a Sola to do that. They work well, but tend to run hot and hum a bit! The previous issue of Photo Techniques had an article on this ;-)

-- Conrad Hoffman (choffman@rpa.net), June 15, 2000.

I had a problem with a thin negative that needed more time for dodging, etc. I bought a sheet of neutral density filter in acetate form for dirt cheap from my local photo store. One layer gave about 1 stop's increase in exposure time. If more were needed, I would simply cut another square and double it. Nothing could be easier.

-- Sam (sselkind@home.com), June 15, 2000.

I use a simple dimmer made up properly on a power board. (Usefull also for changing the speed of your electric drill, etc). Works well, and even if the spectrum changes, well you still need to use test strips. But it certainly allows more control over best enlarger lens aperture and time for burning/dodging. Mine worked out about $30 Australian, say $20 US. Reckon its great! David Strachan

-- David Strachan (strachan@cww.octec.org.au), June 16, 2000.

Thanks for the feed back on my question. I have installed a simple in-line dimmer as a result. It cost approx $15.00 for the dimmer, cord, receptacle and plug. I'll be putting it to use this weekend. Thanks again!

Jim

-- Jim B. (jimzspace@yahoo.com), June 16, 2000.

Dimmers are a hassle, They buzz, heat up, alter the colour temp of the enlarging light ( problematic with VC papers). Get a few neutral Density filters and toss them in the filter draw. I use an ND.6 (2 stops) and have a couple of 0.3's (1 stop) handy in case i ned a longer printing time. Mine are Lee ( or Rosco) lighting filters for theater & Film lights, but kodak wratten filters are just as good...

-- David Carretero (davidcb@teleline.es), July 08, 2000.