Quote Originally Posted by Mike-D View Post
I used red LED brake lights driven by a 12V supply, and red LED Christmas lights with no ill effects. These were great for lighting areas of the darkroom where the main safelight didn't quite reach. The standard test is to put out a piece of enlarging paper with something on it for five minutes. If there is no shadow then the light is safe.
This test is a bit too simple.

You need to use paper that has been pre-exposed to a slight fogging exposure. And it is best to add a test with paper that is post-exposed to a slight fogging exposure.

And five minutes might be a little short, if one is used to using some fairly complex printing regimes.