My little turtle buddies, one in full white paint and the other in chipped white paint, just didn’t show up well, they were more like white blobs. So I used Snapseed to try and sharpen the image up. No luck. Then I went into iColorama and used congruence to give some texture and at least you can see the faceted plates on the back. Then I fiddled with the coloring until it was pleasing. Used a framing app, don’t remember which one. Phonto for the signature and it came out looking pretty good.