Science Buddies: "Ask an Expert"

I am wondering if anyone know the composition of oxides in a standard neutral density filter or other optical filter?

This project is for IB Internal Asesement and a personal project.
I have read the they are composed of cobalt oxide + another oxide for a desired percentage of light block.
I understand that CoO is extremely toxic. Is there an alternative I can use?
I would like to make a ND coating similar to hydro-dipping that would allow a user to coat their own lenses, glass etc.
I have hypersensitivity, and I want to develop this to help not only myself but others with this issue.

Thanks,
Phoenix Mapeso

Hi Phoenix,

Optical coating requires special equipment and is pretty challenging to DYI. To my knowledge, glass cannot be tainted unless with dip coating unless there's a taintable coating on top. Sorry not much of a help in this response.