LED bulbs for alt process darkroom - what's safe to use?

I'm not really keen on buying incandescent bulbs for my newly set up alt process darkroom, but I understand that some LED light bulbs emit UV light as well as visible light. Anyone have a LED bulb recommendation that they have tested as safe?

The plan is for 4 60w equivalent bulbs mounted on the ceiling. These room lights will be on during the entire process. My process at this time will be mostly palladium.

The short answer is you'll be fine - especially with the cheaper low-CRI (Color Rendering Index) LED bulbs.

Most white LED bulbs are made from a blue LED and yellow phosphor. The blue LED will be either 445 or 455nm center-wavelength. Warm-white (2700 to 4000K color temperature) bulbs are more likely to use 455nm, which is better. Iron-based photographic processes are sensitive to about 430nm and a tiny bit above, so not strictly just UV. Blue LEDs, especially the 445nm ones, emit a tiny bit of light below 430nm. Incandescent bulbs also emit a tiny bit of light below 430nm, and even some below 400nm (true UV).

I've read proposals to make very-high-CRI LED bulbs using UV LEDs and broad-spectrum phosphors. I haven't come across any products using this technique, however. It would be less efficient than the standard blue LED designs. So far, it looks like high CRI LED bulbs add a red-orange LED besides the blue LED and phosphors. That kind would still be fine for a darkroom.

BTW, 395nm UV LEDs are becoming more efficient and cheaper. They make great exposure light sources.

David Knierim