I did quite a few campaigns for the COI before it was reduced to just making the odd poster by government cuts after the crash and this one was particularly interesting.
It is a reboot of a previous ad they did which showed bacteria showing up as a red stain under certain light. In the previous version this had been added afterwards, but I wanted to do it in camera.
We did a few tests to establish whether this was possible, then during a two day shoot we used red Day-Glo paint to represent bacteria and filmed under strong ultra violet lights to make it show up. The effect worked brilliantly and makes for quite unsettling viewing.