SparkPrep: fix KDP & IngramSpark book file rejections before you upload
SparkPrep checks your book cover and interior against the exact rules Amazon KDP, IngramSpark, Barnes & Noble Press and Lulu use to reject print files (page size, bleed, spine width, safety margins, ink coverage, CMYK, image resolution, fonts and leftover template marks), explains every problem in plain English, and fixes it for you. Built by an author whose book was rejected 18 times.