Abstract: Non-linear camera models are playing an increasingly important role in computer graphics, especially in image based rendering and non-photorealistic rendering. We introduce ARTcams as simple non-linear cameras, which are unique in combining both geometric projection and non-geometric attributes such as colour into a single model. The geometric component of an ARTcam subsumes many contemporary non-linear cameras, including General Linear Cameras, push-broom cameras, and X-slit cameras. The colour component generalises compositing operations. ARTcams, though, by combining geometry and other attributes generalise yet further. ARTcams can be thought of as lenses (or mirrors) that can reproduce a wide variety of real effects, including aerial perspective, depth of field, as well as both geometric and chromatic aberrations. They can be calibrated for both geometry and colour against real optical devices. It is possible to specify ARTcams by drawing alone. This paper explains and demonstrates the ARTcam model.