Set your phone 8–12 in above the paper. A drinking glass, a stack of books or a phone stand works.
Slide and pinch the picture until it sits on the paper the way you want, then tap the lock.
Draw while you watch the screen, not the paper.
Pin keeps the picture stuck to the paper if the phone gets bumped. Keep the paper's corners and a little of the table in view so it has something to follow. Tap Time-lapse to record your drawing sped up.
As a lightbox
Turn screen brightness all the way up.
Lock the picture, then lay thin paper (printer paper works) over the screen. Tape the corners.
Trace with a light touch, a pencil or a felt pen. Avoid ballpoints that dig in.
Put it on your home screen
iPhone: in Safari, tap Share, then Add to Home Screen. Android: tap Install in the tools, or Chrome's menu › Add to Home screen. It works with no signal after that.
Your photos stay on this phone. Nothing is uploaded. Free, with no ads. Made by Sanpetra Labs in Sanpete County, Utah. v1