Stop guessing where to place your test strips. The ΔStop Test Strip Ruler divides your paper into equal segments in seconds, so every test is consistent, repeatable, and easy to evaluate. Two sides cover four of the most common configurations: 3 and 5 strips on one side, 7 and 9 strips on the other. Each segment is clearly marked with tick marks and segment numbers, letting you position your easel blade or dodging card with precision — no mental math, no eyeballing. Laser-cut from matte black acrylic with UV-printed white markings that won't rub off, the ruler is sized to fit neatly alongside a standard 8×10 sheet. A hanging hole keeps it within reach on the darkroom wall. A small tool that removes one more variable from the printing process. Four configurations: 3 / 5 / 7 / 9 strips Laser-cut black acrylic with UV-printed markings Hanging hole for wall storage Sized for 8×10 paper
