Roughness measurements on Easter eggs? No, we do not want to win the Ig Nobel Prize, the annual award for the most curious scientific project. Nevertheless, what we would like to demonstrate in this application report is by no means trivial, nor is it unimportant when applied to other coating applications. This is what egg dyeing is all about: a coating process that is not done by hand in industry, of course, but with similar steps. A raw material (the egg) exists, is pre-treated in some way (in this case boiled) and finally colored or given a different type of coating. And it is precisely here that roughness plays a major role in every step – it is not without reason that on every paint can it is recommended to first roughen the surface (this step can be omitted in the case of a naturally rough hen's egg). As in our Easter example, the roughness of the surface is therefore checked between the process steps in many machine coating processes.