Gridline: Grid & Value Study

Put a grid over any reference photo and check its values on the same screen.

Gridline is a drawing grid for painters, illustrators and art students who work from reference photos. Import a picture, set up the grid, switch to grayscale or a notan when you need to judge values, and paint with your phone or iPad beside the easel.

■ Free • Import from your photo library or take a new photo • Square or rectangular cells, with any number of columns and rows • Diagonals, cell numbers, line color and line thickness • Grayscale view, a 2-tone notan, and mirror • Paint mode: the tools disappear, touches are ignored and the screen stays awake, so the device can stand by your easel. Long-press to leave • Unlimited projects, each one reopening with the settings you left

■ Gridline Pro (one-time purchase) • Notan in 3, 4 or 5 tones: drag the split points on the value scale and simplify the small details • Fit to canvas: crop to A4, 8×10, 9×12, 11×14 or 16×20 in, or square, in portrait or landscape, and see the real cell size in cm or inches • No ads

Pro is a single purchase, not a subscription. You can restore it on other devices signed in with the same Apple Account.

■ About ads The free version shows one banner ad at the bottom of the project list. The editor, where you look at your reference, has no ads.

■ Your photos stay on your device Gridline keeps its own copy of each reference inside the app. There is no account or sign-up, and your images are never uploaded.

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