Hello Alexandra.  I am painting with a water-based Gouache, not acrylic- based so it can reactivate when trying to touch up sections.  My art has a black painted background so no need to remove the background.   However, the black paint mix seems streaky on the upload. I struggle with how to touch up the smudges using photoshop (see the berry with the black smudged edge).  I am also confused by the scanning figures...my computer shows PPI not DPI.  I used 600 PPI when scanning and maybe that is too high?  I find the black backgrounds shows a lot of white dots in it that would be difficult to correct (they don't seem to show here though).  Also, if I were to upload it to redbubble, do I need to create my own mockup frame?  So much to learn, so I am trying to start off simply.  Wonderful course, I think it is from 2018 and were are in 2021 now so maybe my photoshop version is quite different?  Thanks so much in advance!