Hello,

I am looking for some suggestions to decrease the light intensity from my enlarger without altering color balance. I'm working with a Beseler 45S dichro head, which has a 250W bulb. With either color or B&W materials and 8x10 enlargements from medium and large format negatives, I'm restricted to apertures between f16 and f22 and exposure times of 7-9 seconds. This seems to be outside the optimal aperture range for my lenses and too short an exposure time for effective dodging when needed. Dialing in cyan does help a bit, but even at maximum cyan I can get maybe 1-1.5 fstops. I've heard of using a voltage regulator to decrease the output but don't know where to find one. Doesn't that also alter the spectral output of the bulb, necessitating new filter values for color printing? Thanks in advance for your help.

-- Daniel Lin (kdlin@earthlink.net), February 02, 2002

Answers

Yes, a voltage regulator (called "dimmer" here in Sweden) can be used, but then the light will be more reddish. In my Fujimoto enlarger, a lever svitch puts a piece of metal before the halogen lamp and reduces the light with one third.

A suggestion would be that you use a 100 W lamp bulb instead and learn to use a new filtering.

You can also use a Neutral Density, grey filter, in front of the lens. Get a high quality filter like the B+W 102, that will reduce the light with two stops, or a B+W 103 for a 3 stop reduction. With this option you don't have to change your filtering.

-- Patric (jenspatric@mail.bip.net), February 02, 2002.

Sheesh, I forgot to change to my new email. The mail.bip.net doesn't work anymore. :-/

-- Patric (jenspatricdahlen@hotmail.com), February 02, 2002.

I'd try the ND filter...the 45S uses a quartz projector lamp...btw, we have 2 of those heads in our lab, and my typical exposure for an 8x10 sized print is in the 8-10 sec range at f11.....maybe your negs are thinner than an avergae one for us though? A 5x7 sized b/w print is usually around 4 sec at f11 for RC prints off a 4x5 TMX neg ....for the little color work I've done with them, my exposures have been similar....I'd steer clear of the cyan filtration as much as possible....you could contact Beseler as well but I think the 250 watt lamp is it for the dichro heads. Another thing to try would be to switch to the 4x5 diffusion chamber only if you're using one of the other ones...the 35 and 120 chambers are supposed to increase the output 100%....we have those too, but I use the 4x5 for all formats. Good luck.

-- DK Thompson (kthompson@moh.dcr.state.nc.us), February 04, 2002.