Safelight for B&W contact printing

[Kevin Crisp]

The same bulb is available elsewhere for $29 or so. They last a long, long, long time. The bulb is commonly used in street lighting -- there is nothing unique about it for this application.

The filters can be replaced with Roscoe filters, you cut them and put them between the sheets of glass and tape them up. I just rehabbed a Thomas with broken filters and a bad bulb and a rat's nest in it. I used the color of the gel that is widely recommended for this -- R19 "Fire." It works fine. Add a little tissue paper in the glass sandwich before you tape them up. Or you can by new filters from B&H.

[Oren Grad]

For at least 20 years now I've used a Jobo Maxilux. It's a compact LED lamp that doesn't need to be wall- or ceiling-mounted - perch it somewhere convenient, plug it in, and you're all set.

[Leigh]

Permit me to explain the difference between the Thomas Duplex and other safelights.

Here are comparative spectra of four common light sources. At upper-left is regular light bulbs:


The Thomas uses a low-pressure sodium-vapor lamp that emits only yellow at any significant intensity.

Its spectrum includes other colors at very low intensity, not significant for paper but may be for film.
That's what the filters are for.
Here's the spectrum:



In contrast, any thermal light bulb emits strong colors across the entire visible spectrum.
That requires significant filtration for paper as well as film (if useable at all with film).

LEDs can be highly monochromatic, but only very powerful ones emit significant amounts of light.
Also, there are no yellow LEDs. Those marketed as yellow contain both red and green emitters.

- Leigh

[Leigh]

Well the Thomas Duplex bulb is $120 at Freestyle, but where do we get new filters?
For that matter, how many of them are still alive?

My wife went to South America for Halley's Comet in 1986.
She came back with lots of photos of it and other subjects.

I built the darkroom as a cheaper (and politically better) alternative to sending the film out.
The Thomas Duplex was bought used.

The TD safelight still works fine today, just as it did when first installed 30 years ago.
I bought a replacement bulb from B&H at the time. It's still sitting in the drawer.

- Leigh

[N Dhananjay]

Another reason for liking the Thomas is the fact that it is less tiring on the eyes. Dim safelights mean that your pupils are constantly adjusting to deal with the extremes of a dim safelight followed by the large amounts of light required for printing exposures on contact papers. This used to screw up my print evaluation. I now have a Thomas that is going constantly and I have print viewing lights switched on with a footswitch and adjusted in intensity to ensure my eyes are not thrown off.
Cheers, DJ

[MartinP]

It looks as thought the OP is setting up their first darkroom. All of the answers above seem to be suggesting different types of safelight based on fashionability.

Decide what paper will be used (traditionally a silver-chloride based paper), follow the manufacturers datasheet to choose the type of safelight filter.

No specific brand or design of safelight is essential so long as it's output is consistent with the requirements of the paper. All sorts of safelight are used by somebody, somewhere - the variables of size of room and practical availability of the safelight are important factors.

[dwill]

Thanks for all the feedback everyone. Martin, will check the paper as you mentioned. I will only be doing contact prints using Lodima paper and the new adox lupex paper, developing in amidol. Using mostly FP4 film and developing with abc pyro. For anyone who cared to know exactly my paper and materials.
I have looked for a Thomas duplex and found one on eBay for $270. I seriously doubt it sold and probably won't unless they drop the "2". Lol. I will keep looking and just test a few options (bulbs) to see what works.

[sepiareverb]

Kodak bullets and two-ways here. They are cheap, and I have a bunch of them. Three bullets over the sink, a two way over the enlarging counter and another over the wash sink. Then another bullet at the desk. Plenty bright, perfectly safe after testing and adding some ND to the light over the developing tray. I have light grey walls, and a white ceiling.

I use night light bulbs, and appliance bulbs, low wattage, dirt cheap, and long lived. When the incandescent wars began I stocked up on bulbs, I don't think I've gone through one package yet, so am set for life.

I've got a collection of filters as well, some eBay, some from a local shop closing doors.

Ceiling height in my darkroom precludes a TD. The bullets are not a lot shorter, but they hang out of the way, over the sink and desk. I approached the darkroom like one approaches a kitchen: some general lighting and then more specific task lighting.

[HMG]

I have a small (roughly 8'x8') darkroom so I didn't think I needed the Thomas light I was saving for many years. I installed it to test before selling. It's such an improvement that I kept it. I did have glass cut and build filters. Keep in mind that the filters aren't needed for typical use, but in my case I had to cut down the light a bit.

I consider it a luxury.

BTW, it's getting tougher to find Rosco filters at photo stores, but I've had success at a local shop that deals with theatrical lighting.

[Tin Can]

So the secret to a Thomas Duplex is the narrow and correct spectrum bulb. Yes, I realize the Thomas Duplex box has good adjustability with flaps.

The LED I use I selected based on it's correct and tested spectrum.

Apples and lemons...