RESUMO
Structurally coloured materials that change their colour in response to mechanical stimuli are uniquely suited for optical sensing and visual communication1-4. The main barrier to their widespread adoption is a lack of manufacturing techniques that offer spatial control of the materials' nanoscale structures across macroscale areas. Here, by adapting Lippmann photography5, we report an approach for producing large-area, structurally coloured sheets with a rich and easily controlled design space of colour patterns, spectral properties, angular scattering characteristics and responses to mechanical stimuli. Relying on just a digital projector and commercially available photosensitive elastomers, our approach is fast, scalable, affordable and relevant for a wide range of manufacturing settings. We also demonstrate prototypes for mechanosensitive healthcare materials and colorimetric strain and stress sensing for human-computer interaction and robotics.