I visited Roubaix, or more properly, Tourcoing, to see Mat Collishaw’s Thresholds, which I missed when it was first shown in Somerset House in 2017. It reconstructs in VR Fox Talbot’s first exhibition, put on by the British Association for the Advancement of Science at King Edward’s School in Birmingham. I haven’t always been persuaded of the virtues of VR, but on this occasion it has the surreal and convincing ability to make one able to see the original display cases as they were in 1839, a remarkable effect of simulation.