Thomas Duplex Safelight?

nsurit · May 8, 2009

I have a Thomas Duplex Safelight with the proper filters for B&W. I know that the yellow edged filter goes in the Body and the red edged filter goes on the vanes. The is a colored side to each and a side I will call the "white" side. What is the proper orientation of the "white" side? Toward the light or away from the light? It may not make any difference, however if there is a correct orientation, I'd like to get it right before I hang it from the ceiling. Thanks in advance, Bill Barber

David A. Goldfarb · May 8, 2009

I've always seen them white side in I think, and that's how I do it.

nsurit · May 8, 2009

Thank you. I'm header to the ladder. Bill Barber

RJS · May 9, 2009

I've never thought the Thomas light made much sense for smallish darkrooms. They seem to be very powerful, lots of light, and have to hung in the center of the room. /which casts shadows wherever I want to work, making them virtually useless. Do others view them this way?

dpurdy · May 9, 2009

I can't stand the buzzz. I gave mine away to a great relief.
Dennis

msage · May 9, 2009

RJS said:
I've never thought the Thomas light made much sense for smallish darkrooms. They seem to be very powerful, lots of light, and have to hung in the center of the room. /which casts shadows wherever I want to work, making them virtually useless. Do others view them this way?

Mine is pretty much in the middle of my 12x8 darkroom. No shadows to speak of and the hum is ok for me. It is loudest when first turned on, quiets down as it warms up. It was the best $10 I ever spent.
Michael

pentaxuser · May 10, 2009

I assume that the Thomas( I wrongly called it the Thompson but that's a gun, isn't?) is a sodium light. I say this because the DUKAs which are sodium make a similar buzz. I think it does quieten down after a while but it is helped by the fact that you get used to it and notice it less.

Just as a matter of interest why do sodium lights buzz?

pentaxuser

eddie gunks · May 10, 2009

dpurdy said:
I can't stand the buzzz. I gave mine away to a great relief.
Dennis

the newer ones i have have much less (read no) buzz.

i think they are great. no shadows. if you have shadows use two. i call it my dim room. i will never go back to red lights again. works for wet plate collodion as well.

jgjbowen · May 10, 2009

A Thomas safe light (mine was purchased new about 18 months ago) is the BEST thing to happen to an Azo printer since Amidol!

Lee L · May 10, 2009

A sodium vapor bulb, like a fluorescent lamp, needs a ballast to operate properly, controlling current so that the lamp components aren't destroyed. There are magnetic ballasts that operate at the frequency of the AC current, and electronic ones which are designed to operate at higher frequencies, often near 20 kHz. The magnetic ballasts at 60 Hz can be heard, but electronic ballasts are quieter and operate at a frequency above what most humans can easily hear.

I worked once in a darkroom that had a Thomas safelight installed in a very large space with high darker ceilings. With the RC paper that we used, Kodak's II and III iterations, I had to put the vanes all the way down to prevent paper fogging from just a minute of exposure to the safelight. Processing was done in a closed roller transport system, so it was only the handling and exposure time before that (with exposures typically at 10 seconds or shorter) during which the paper was exposed to the safelight.

Lee

outwest · May 11, 2009

Yes, you definitely need to run a test with paper flashed to threshold level. I have to have both vanes closed and the one towards the enlarger 3/4 covered to ensure safety of normal exposure, burn and dodge, and development.

resummerfield · May 11, 2009

outwest said:
....... I have to have both vanes closed and the one towards the enlarger 3/4 covered to ensure safety of normal exposure, burn and dodge, and development.

Interesting..... that is exactly what I have to do--close both vanes and then cover them. In my case, I cover both vanes with cardboard about half way. But it is a very nice safelight, and very bright even when covered.

Thomas Duplex Safelight?

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