Originally created for the Wellcome OnLight exhibition (London, 2015), also later featured in UCL Spark festival, it was part of the contribution of UCL BORL group to these two public engagement events. The BORL bulb was a hollowed out incandescent bulb filled with lightly scattering silicone, and illuminated from below with a 40W RGB LED. Three large dials on the front of the enclosure adjusted the amount of blue, green and red colour intensities. Unlike majority of LEDs which have focused illumination, the visitors experienced a unique visual of colour mixing due to the volumetric scattering occurring inside the bulb. Now, the bulb has a permanent home in UCL Medical Physics museum.