Hi guys :) I'm designing an automatic soap dispenser, in which the soap particles contain phosphors. These will emit visible light in the presence of UV light. I intend to have a small UV light source underneath the dispenser. Thing is, its really bright in bathrooms, and its tricky to see the UV/phosphor glow from the soap unless one is in the dark Would there be any way to block out the ambient bathroom light via an optical filter, which only lets in the light from the phosphor particles? The optical filter would be installed on the end of the dispenser, such that you could see the soap particles glowing if you looked through the filter, but everything else would be dimmed. Thanks, just not too sure what sort of wavelengths the emitted light is, or whether it would be possible to isolate this.