Composting machine, thermogram footage. Thermography records the temperature of surfaces by detecting long-wavelength infrared radiation. The colours show variations in temperature. The scale runs from white (warmest), through yellow, orange, red and purple to blue (coldest). This footage shows cold organic material (blue-black) being placed inside a composting machine. The heat produced by the decaying material is visible (bright yellow) when the lid of the machine is opened, and is also visible radiating through the window on the side of the machine.