Red led Ribbon.

[maxb1837]

Hello
Is a led ribbon with a wavelength: 620-625nm sufficient?
I think so, because I use my bicycle rear light which I want to replace with
a fixed light source.
Thanks

[Richard Wasserman]

This old discussion may be useful

https://www.largeformatphotography.info/forum/archive/index.php/t-151417.html

[koraks]

Is a led ribbon with a wavelength: 620-625nm sufficient?

You'll need to test.
One bicycle rear light is a lot less bright than a string of similar LEDs.
In my experience red LED strips are usually not safe 'as is' without additional filtering with e.g. rubylith and/or dimming them to a lower light level. I'm currently using 660nm strips and have multiple layers of filter material as well as dim the strips to a low level that's safe. If I have these on at full strength without a filter, the room is hella brightly lit, but any silver gelatin paper also fogs within a minute or two. This is with several meters' worth of LED strips though. I like to have the light dispersed across the room, hence the many strips.
More info here: https://tinker.koraks.nl/photography/some-light-to-the-darkroom/