View Full Version : Safelight Wavelengths

Chuck Peacock
28-Dec-2010, 21:01
I'd like to replace my safelights with LEDs.

In theory LEDs should make a perfect safelight source since (excepting so-called white LEDs) they emit on a single wavelength. This also presumes that someone makes an LED that falls into one of the sensitivity "gaps" in the paper spectrum.

Did Kodak or Dupont (or anyone else) ever publish the spectral characteristics of the various safelight filters that were recommended for various photo papers?

I suppose instead of starting with the safelight data you could start with paper spectral sensitivity, but I don't seem to have a good source for that either.

Any ideas?


(If this is restarting an old thread -- sorry. I did look but couldn't find anything.)

28-Dec-2010, 21:11
The wavelength information is in Kodak's technical information.

Google will get you there.

28-Dec-2010, 22:34
Comparing the Luxeon Datasheet (http://www.sparkfun.com/datasheets/Components/Luxeon-I.pdf) with the Kodak Safelight filter (http://www.kodak.com/global/en/professional/support/techPubs/ti0845/ti0845.pdf) datasheets it looks like Luxeon Red LEDs are plenty safe. Red-Orange Luxeons should work as well and might be closer to the "light amber" safelights. Amber Luxeons are a little too close for comfort IMO. I would go with Luxeons or CREE Leds as they are the best LEDs out there. A single 1W Luxeon gives off enough light for my enlarger area.

28-Dec-2010, 22:39
Ilford has the spectral data on its web site. Of note there is some overlap in sensitivity with a typical safelight filter, thus the need to test in actual darkroom conditions.

Jay DeFehr
28-Dec-2010, 22:57
I bought a cheap, red, spiral fluorescent bulb from a clearance store, and it works great! My darkroom has never been so bright.

Eric Woodbury
28-Dec-2010, 23:15
this is the perfect season. Red LED Christmas lights. That's what I'm using. Gives a nice illumination throughout the DR.

Henry Ambrose
29-Dec-2010, 06:59
Search this site - this has been discussed at length. What you want to know is the output of the particular LED you want to use. For that you'll have to consult the manufacturer of the LED.