LESSON LEARNT: don’t be cheap, and doublecheck before purchasing! To be fair, the BLB florescent tubes did pick up the ‘bug spray’ label, which means it’s at least 310nm (UV light wavelength-strength is measured in nm; where 200~nm will cause polymerisation, 320~nm is used for low level tanning; 350~nm onwards is used for foresenics/germicide/blacklit parties, 400~nm onwards is dangerous and used for industrial production) However, for my project to work I need at least 385~nm onwards which means these lights are way way way too weak! adding additional lightbulbs won’t help, because it’s a wavelength issue not a brightness issue. Basically it means that there is too much white light passing through and not enough UV light being produced. This becomes really apparent when you look at the picture with my desk stuff – there’s enough white light going through that the twinnings tea box is still faintly yellow.