If seventeenth and nineteenth century exhibition venues generally opted for red as the ideal colour for hanging paintings, the eighteenth century stood out. Following on from Newton’s works, green was progressively singled out in Europe as a neutral and soothing colour well-suited to highlight Old Masters as well as contemporary works, without affecting the way they were received by the viewing subject. The article analyses this phenomenon, retracing its theoretical implications back to its origins. Thus, it touches on a rather neglected aspect of eighteenth-century collecting habits, and points to the use of colour in the processes of reception of art works in the Enlightenment age.