Painting with the whole screen
⛶ Fullscreen gives the image the entire display and holds the current rotation, so leaning over the paper does not spin it. Tap it again to come back. ☀ beside it keeps the screen awake, so it will not dim with a brush in your hand.
Is there a phone app?
This is it — add it to your home screen and it behaves like one. On iPhone, open this page in Safari, tap the Share button, choose Add to Home Screen, and confirm. Launch it from the new icon and it opens full screen with no address bar or browser buttons, keeps your image and settings between sessions, and works with no signal at all — useful outdoors, or anywhere your hands are wet and your data is not. On Android, choose Install app or Add to Home screen from the browser menu.
1. Frame your paper
Load a photograph, then open Crop from beneath the image in the Photo view, and enter your paper and square sizes. The whole photograph stays visible; drag the frame over it and pinch to resize it. Anything dimmed is being cropped away. The frame always matches your paper, and Swap portrait / landscape is right there if it is the wrong way round.
2. Choose what to study
Photo keeps detail. Colour finds broad wash families; place it over grayscale to see structure without competing colour, or over Paper to drop the photograph entirely and see the washes alone. The Paper and Image buttons beside Grid switch that while you work; tap Image twice to swap grayscale and colour. Notan reveals value masses. Grid works over every view.
3. Isolate one wash
In Colour mode, tap a swatch in the palette strip to show only that colour; everything else falls back to the reference underneath, so you can see exactly where the wash belongs. The first time you do this the reference switches to Paper, to show that the photograph can be taken away entirely; after that the ground stays wherever you leave it. Tap the swatch again to bring the other colours back.
4. Mix a wash
Tap the image for a large sampled swatch. Colour mode samples the pure reduced colour. Photo mode averages a small area. Use it as a relative guide, then judge pigment on your paper.
5. Save a reference
Save any individual view or a 300-DPI three-panel sheet. On iPhone, use the share sheet to save to Photos, Files, or print.
Grid convention
Columns read left-to-right and rows top-to-bottom. Partial cells appear at the top and right because the physical grid is ruled from the bottom-left.
Everything runs locally. Your photograph is never uploaded.