I try to print frames for my litophane pictures but 1 side always getting faulty.f
More info would be really helpful. Printer, filament type, part orientation etc. You can even upload the .3mf file which is the best way to help solve issues.
From the picture it looks like you are printing the frame vertically. The artifact you are seeing might be the result of a scarf seam. Here is the wiki article regarding seams.