By "LED" do you mean the commercially available LED based lamps? They do vary as suggested already, but they will be fine - it is not easy for an LED to emit very much light too far off its intended colour. Put it too close however and it will fog.
If you make your own from quality LEDs and drive them at the correct current, out of band emission can be reduced to minimal levels allowing brighter light in theory than using bought lamps - but in practice I doubt it is worth the effort. Just do the usual safelight tests and you can certainly expect to end up with brighter light than the usual low-cost safelight with filters.
I dislike red light (too gloomy) and use orange or amber LEDs in a home-made safelight. Unfortunately the only orange/amber ready-made LED lamp I could find locally emitted too much out of band to be useful (which just goes show how far you can take theory sometimes! )...
Last edited by Bob F.; 11-05-2007 at 08:49 AM. Click to view previous post history.
Reason: Syntax got messed up...