A research team led by Monika Aidelsburger at the Max Planck Institute of Quantum Optics (MPQ) and the Ludwig-Maximilian University Munich (LMU) has identified a colour of light at which atoms become selectively “colourblind”: At this wavelength, the light has no effect on excited-state atoms, but strongly confines atoms in the ground state. The results, published in PRX Quantum, provide a powerful new tool for analogue quantum simulation and novel computing architectures.