Measuring board

Print at 100% on A4. Do not fit to page. Then check: the two top marker centres must be exactly 150 mm apart, and top to bottom 237 mm. If not, the print scaled and every measurement will be wrong.

1. Lay this sheet flat on the table. Tape it down so it cannot shift or curl.
2. Lay pressed scraps on the same flat surface, beside the board, not touching each other and not overlapping it.
3. Shoot from above with all four markers in frame. Roughly square-on is fine — the board corrects the angle.
4. Do not use the ultra-wide lens. Use 1× or 2× and stand back. The board corrects perspective; it cannot correct the barrel distortion of a wide lens, which bends straight edges near the frame corners.
5. Keep the scraps in the middle two-thirds of the frame.
6. Even light. No hard shadow across a scrap edge, no flash glare on the board.
7. Contrasting ground: a white sheet under dark scraps, a dark one under pale.