Fluorescence pics

[Scythanith]

This is what the light should exhibit:

This is what the filter should remove:


You don't want the blue, hence the filter that blocks the band your transmitting intentionally. The corals proteins are excited by the wavelength and transmit light back at a different spectrum which you can see thanks to the filter removing the blue. Hence, most NightSea photos have a beautiful orange/green/yellow look.... but no blue.