Do indents glow on an invert?

Courtney • 💜 Violet Mae, born May 2021 🦊 Creedence Asher, born December 2018 👼🏻 Angel baby, March 2018 (due 11/10/2018) 🍊 Clementine Everly, born May 2017 👼🏻 Angel Baby, June 2016 (due 3/2017)
I read somewhere that indents won't show up when a picture is tweaked/inverted. Is this true? I tested this morning at 8dpo, and the line was super faint and not very pink. Immediately took two more tests (thank you, Wondfo), and they were negative. Really hoping this isn't an indent!