Thomas Duplex Safelight...

[ChristopherCoy]

I recently visited Valerie and was able to see the Thomas Duplex in action. As compared to my multiple 5x7 safelight strung along the wall, the Thomas Duplex puts out LOADS more light!

I've recently been looking into them on the bay, but I wonder if they are a wise investment.

Replaceable bulbs are about $100.
ETA: bulbman.com seems to have them for $34. (SOX35)

What are your opinions on the setup?

ETA: looks like the bulbs are 18,000 hour. I was able to find some good info on LFF.

My "darkroom" is actually the laundry room and its about 6x12'. Would the noise be overbearing? I don't remember Val's being noisy.



I'm still interested in hearing any tips for use in smaller darkrooms. Some people have posted that they've had to close one side with black foam board.

 

[ParkerSmithPhoto]

Chris,

Be sure to check out my thread "I (heart) Thomas Duplex."

You can find instructions there for a complete redo of the filter packs. It's easy to add extra diffusion to cut down on the light dramatically. I do have one side masked with black foam core for when I am printing fiber finish prints. For quick RC proof work I usually have it wide open.

Mine has a tiny hum that is easily masked with not very loud music.

Love it!

Parker

 

[ChristopherCoy]

Thanks Parker.

Btw... Check out my new girl! DLT Dragonslayer, or as we call her, just Slayer.

 

[Richard Jepsen]

I taught in a DR with a Thomas Duplex. When I had to replace the filters I decided to move to a Kodak Utility 10x12 OC safelight with optional Red safelight over the trays and a few small OC lights in deep corners. Each station had a Jr Lab red safelight. Avoiding noise was a benefit. In a home DR the Duplex would be overkill; too bright and too loud.

 

[lightwisps]

Love my Thomas

I use one and absolutely love it. It makes a bit of noise, but is drowned out by the radio and my wife wanting to know what I am printing. It is a bit bright actually, so I just put a thin white towel over it. This is my second one, have never had a bit of trouble including the bulb. I highly reccomend one. Don

 

[TheFlyingCamera]

I would find it beyond overkill in my small darkroom (7'x8' with a 6'6" ceiling). Can't speak to noise level - my memory of them comes from working in large community/university darkrooms where the extractor fans created more noise than the safelight.

 

[Ken Nadvornick]

Not sure where these references to noise are coming from. My Duplex has always operated dead silent. No noise No hum. Nothing.

My filter pack has also been modified with the Roscoe #19 Fire filter, so it's completely safe out to at least 60 minutes (tested), even with the vanes wide open. With an extra replacement bulb stashed for safekeeping, I'm probably good-to-the-grave.

These days the Duplex does, however, share significant time with a DIY red (635nm) safelight, filtered through Rubylith. Some of the VC and/or Eastern European papers like that guy a lot better.

Ken

 

[ChristopherCoy]

Not sure where these references to noise are coming from. My Duplex has always operated dead silent. No noise No hum. Nothing.

According to a thread on LFF, when bulbs begin to go bad they can cause the ballasts to make noise. It can sometimes be remedied with a new bulb.

This is what was posted:

I spoke to someone at Thomas Instruments today. They are still selling parts for the Duplex safelight. My question was: why is one of my units so noisy? Answer: Sometimes an old bulb will strain the transformer so much that it is damaged, but in any case, a dying bulb will cause the transformer to be noisy. The transformer is called a "TRD transformer" and costs $72. I have three units (two in one large group darkroom, one in a smaller darkroom. The smaller darkroom's unit is almost silent at all times, yet nice and bright. One or both of the others are nastily noisy.

The nice Thomas rep. suggested trying the bulb from the quiet unit in both of the others. If peace returns, the culprit was the bulb. She said that a properly-functioning unit takes no more than 5 minutes to reach full intensity, so one that takes longer probably has a dying bulb, and/or a bad transformer.

Hope others find this info as useful as I did.

 

[Ken Nadvornick]

Ahh... If true, that would explain it then. Thanks. My current bulb is nowhere near bad.

And another data point to keep in mind here. When the Thomas Duplexes were discontinued everyone thought that was it. If you wanted a new unit you were out of luck. Just take your chances with used ones.

That's not necessarily the case...

Here's a pair of [Edits] of mine from an earlier post on the subject:

[Edit: For those who may wish to purchase a new low-pressure sodium safelight, but thought they missed the boat when the Thomas Instrument Company [discontinued the Duplex], check out this LPS-based OC-1012 Safelight from the Sebastian Darkroom Products division of California Stainless Manufacturing. California Stainless is the OEM manufacturer for many of the Arkay lines of stainless steel products. Email them and ask for a paper catalog. It's pretty cool.]

[Edit2: My current (January 2012) price list shows the OC-1012 Safelight (model #72882) at $370.00, and the LPS replacement tubes at $135.00.]​

So if you're Jonesin' for a brand new unit, it's still possible to get a nearly identical one.



Ken

 

[ChristopherCoy]

SWEEETT!! I just sourced one for $50!

 

[ChristopherCoy]

The Duplex that I sourced for $50 just arrived. I plugged it in and it works, and the doors move up and down fine. The filters don't appear to be in the best shape, and it looks as if they were taken apart at one time and probably replaced with something else.

The hum of the thing isn't so bad. It's a steady, low level hum, and reminds me of something you'd hear from a fridge or chest freezer when the compressor is running.

I'll be looking into replacing the filters, so if anyone has tips if appreciate them. I seem to remember Rosco "Fire" for the red ones, but what about the yellow.

Here's a few pics:



There's just a little bit of damage here . The left seam doesn't lay flat.



And here are the filters. The red ones seem to have a green layer on the outside, I would assume someone put there to block some of the light.



And the iPhone camera does funny things in this light. The wavelength is really visible.

 

[George Nova Scotia]

Those filters are toast. When you take them apart you will likely find they are gell and paper. The rosco fire is close to the OC filter. You should also pick up a sheet of diffusion material as well. If you need red filter for certain papers get a red sheet as well. I think it cost me less than $30 for the bunch and I'm set for life.

 

[ChristopherCoy]

Thanks George. I'm reading a few threads on a few different forums to find out whether I'm going to try and fix them myself, or buy a replacement set from freestyle.

I've read that the Roscolux Deep Amber for the red filters, but I'm not finding anything for the yellow.

 

[ChristopherCoy]

Thanks, going check that one now.

I just read on LFF that the Deep Amber for the yellow filters and the Fire for the red filters were used by others.

 

[Ken Nadvornick]

Chris,

What you're really trying to do with a low-pressure sodium (LPS) safelight like the Duplex is to remove the residual blue and green light that is emitted as a consequence of the argon and neon intentionally introduced into the tube during manufacturing. These gases assist in the striking of the lamp, and help account for the weird colors you see at initial startup before the sodium color takes over.

It's these not-visible-to-the-eye blue and green spikes that are the source of the Duplex's reputation for fogging paper, not its overall brightness. See here for an example of the output spectra from an LPS tube. (Fourth example down the page.) Note the much dimmer blue and green bands to the left of the predominant yellow. There is also a red band to the right, but that of course does no harm.

The Roscoe #19 Fire gel will transmit about 35% of the sodium yellow, while blocking essentially 100% of the blues and greens. And that 65% reduction in intensity of the yellow is usually welcomed by most people with small darkrooms. Often it's still hard to see the image on the easel even at 35%, so the vanes must still be closed while focusing. This is what I must do. See here for a transmission graph of the Roscoe #19 filter gel.

Ken