I'm new to darkroom work and just acquired an Omega B600 enlarger with a Dichoric head. It seems like there is some lilght leakage around the foam rubber seal for the negative carrier. Although there are adjustment screws, I can't seem to get the head to seal completely. Will this be a problem?

-- Scott Flathouse (scott@pan-tex.net), March 16, 2000

Answers

Scott, every enlarger I've ever printed on has had varying amounts of light spraying out from around the negative carrier. It's not a problem as long as none of that overspray is reflecting down onto your easel(paper), and that the negative carrier is being pressed flat.

-- Paul Swenson (paulphoto@humboldt1.com), March 17, 2000.

I have read books by people who were really fussy about this. They say you must completely seal any light leaks from your enlarger, or your prints will all be fogged. I sure read some interesting recipes which made me wonder if those people ever considered the build-up of heat in the head when they advise you to also seal the ventilation openings in the head, or if they ever really tried that. Personally, I would also find it quite bothersome to use tape to seal my negative carrier. How should I do that in a way still allowing me to change the negative w/o having to de-tape and re-tape?

Like most (all?) other enlargers, mine also has some light leakage, and I have never observed any fogging so far. There is a chance that fogging occurs when the light leaking through those slits shines directly on unprocessed paper, or on paper in the developer tray. If you want to make sure, make two safelight tests, one with the enlarger off, and one with the enlarger lamp on for about twice a typical exposure time. Place the test sheet at the most exposed position where paper is likely to lie.

-- Thomas Wollstein (thomas_wollstein@web.de), March 17, 2000.

Many (most?) enlargers leak a small amount of light around the carrier. It's usually of no consequence, but painting the darkroom walls around the enlarger dark is one countermeasure. The rest of the darkroom should be light colored. Do your fog test just the same way as a safelight test- find a white light exposure that fogs a piece of paper to light gray after full development. Now, give a new piece of paper the same exposure, then lay some coins on it. Put it under the enlarger and do a several-times-normal exposure with the lens cap on. Now process the paper. If you can see any outline of the coins, you have a fogging problem. The pre-exposure is necessary to make the test sensitive enough. Fog is never visible in the highlights of a print- it only adds to the midtones and shadows, dulling the result.

-- Conrad Hoffman (choffman@rpa.net), March 17, 2000.

Conrad's test is good. A much rougher test is to put the lens cap on, turn out the safelight, put your head on the baseboard, look up at the enlarger, and turn it on. Can you see any light from the enlarger?

You probably can, which isn't good news. Now take the lens cap off, with the aperture at a typical setting. Is the light leakage significant, compared to the light from the lens?

-- Alan Gibson (Alan@snibgo.com), March 17, 2000.

I use a lady's black headband stretched around the bottom of my enlarger head. After I lower the head to the carrier, I push the headband down around the light leak. It takes about 5 sec.

-- Bob Klein (photobk@mindspring.com), March 23, 2000.

The documented discussions about light leakage around the enlarger are generally a beat up. Like gardening books I reckon a lot of authors just copy stuff from book to book. Unless the leakage is really bad, and shining right onto your paper, there will be no problems. I have more leakage around my dark room door.

A test will show any problems.

-- David Strachan (strachan@cww.octec.org.au), March 26, 2000.