| abstract |
A product is specified which has a substrate and a paint applied thereto. In a first and in a second area element, the paint application comprises in each case at least one color layer (32) with a retinal protein, which shows a color change on illumination. In at least one of the surface elements, a functional layer (33, 33 ') is present, which changes the proton availability for the retinal protein in the relevant surface element, so that the color change of the retinal protein in the first and in the second surface element shows a different time dependence and / or photosensitivity. |