How to filter out blue light?

aegimius

For some experiments I need to be able to filter out blue light with either special light bulbs or a screen around the bulbs. It seems an orange coating on the bulb or an orange screen around the bulbs will do the trick, but I need to filter out as much blue light as possible. Something like 99% would be good.

Will an orange light bulb do the trick, to filter out blue light produced by the burning filament? How can I tell, any specifications to look for when it comes to orange light bulbs, or any inexpensive way to test the wave lengths of the light going through the orange filter or coating? Thanks.

elect_eng

You need to be more specific about the spectral response. Is it OK if you also filter green and UV light? There is a commonly available amber colored filter used in safety glasses for Argon-ion lasers. It is similar to that material used in blue-blocking sunglasses. It works very well but also blocks green and UV light.

This site might have some different options to consider.

http://rosco.com/canada/filters/permacolor.asp

aegimius

Thanks for the link. No, it doesn't have to filter out green, and I would prefer it doesn't. It only has to block blue. As far as UV goes, it would be nice to block most if not all UV, but it's not necessary for what I am doing at this point. Do those orange color coated "party light" bulbs they sell at hardware stores or Home Depot effectively filter out blue light? I appreciate your help.

elect_eng

Honestly, I have no idea what those party lights are, so I can't say if any blue gets through. I know that the amber filters block effectively all blue and most green light. I can say this because I've used them for safety when using Argon-ion lasers. A 6 W Argon laser with all blue and green lines lasing is completely invisible through the amber filter. Given the sensitivity of the human eye, this means that effectively all blue and green light is blocked by this material. I'm pretty sure this material blocks most UV light as well because you will see it used as protection on UV lamps.

If you must pass green light and block blue and UV only, I'd suggest calling a filter manufacturer for advice. However, if the Argon-filter is acceptable, then you can find this material very easily in optics catalogs, or buy a cheap pair of amber sunglasses.