Question: curved grating

Hi, DarkGreen - we had worked on removing curvature but the guy working on that project left, so no progress recently; for a single cross section of the image, however, it doesn't much matter. As to the grooved side or not, I'm not sure but @cfastie posted an article which may have some clues, especially in the long comments section: http://publiclab.org/notes/cfastie/2-12-2013/grating-angle-dvdr

This post by @MrBumper may also hold some useful information: http://publiclab.org/notes/MrBumper/01-11-2015/preparing-a-dvd-r-to-act-as-a-diffraction-grating

Just simply crop it to line and upload it manually.