MicrobeHunter.com Microscopy Forum

Hi folks. My brother is looking for a narrow range blue filter.
I understand the exact wave length doesn't matter provided he knows what it is. It needs to be plus or minus about five percent. Just something to cover the transmitted illuminator. Any ideas would be helpful
Thanks, Greg

He'll probably need to look into sputter-coated filters...which are not cheap.

Chroma sells a broad range of these filters, but I'm not sure if they make them in a format compatible with your brothers setup: https://www.chroma.com/ (look under single bandpass filters)
Edmund often has cheaper options; the OD 2.0 filters may meet his needs at a better price: https://www.edmundoptics.com/c/bandpass-filters/617/

Thanks. I forwarded the info to him. He was very appreciative

A bit late

on retail, there are filters for Astrophotograpy; not cheap too
https://www.baader-planetarium.com/en/filters.html

Otherwise you can use a blue LED - more energy efficient! And they have pretty well defined wavelength and narrow band.
I use the screen of my phone (OLED), displaying a pure blue screen as light source; not very bright, but quick and neatly blue. Just search a blue image and slide the phone under the condenser.