Colour and Colour reproduction has been a detailed element of photography since the beginning of the art. From how we represent colours in black and white to create soft tones, vivid colours of landscapes, to the accurate reproductions for analysis. Modern digital cameras have a detailed and extensive assortment of colour tools internally. From correcting for lens defects and distortions, to compensating for sensor design, there is a huge amount of stored knowledge in the camera bodies we own. How can we access and understand these? How is this knowledge built? And how can we manipulate and improve colour in our open source tools for photography? William will explore the history of colour in photography, detail how cameras reproduce colours, and demonstrate ideas, tools and techniques for colour effects in the open source photo editor darktable - a non-destructive and extensive professional photo editing tool for photographers.