Sumi, India and walnut ink in Easel by Zaweba
Grind sumi ink on the stone for darker ink, and try India, walnut and acrylic ink or the ink wash in Easel by Zaweba. How each one suits different work.

Grinding ink on a stone is one of the quietest rituals in art. In East Asian brush painting, you rub an ink stick against a wet stone until the water turns black, and the longer you grind, the darker it gets. Easel by Zaweba keeps that ritual for its sumi ink, and adds three more inks in version 1.1 beside the original ink wash.
Sumi ink and the stone
Sumi ink is ground on the stone in Easel, and longer grinding makes darker ink. That gives you a natural way to control value. Grind a little for pale grey, more for a rich black.
Traditional ink painters often prepare more than one strength before they start. A practical way to work in Easel is the same: decide how dark your darkest strokes need to be and grind with that in mind. Lay in the pale distances first, then the middle values, and finish with the boldest blacks.
Sumi ink is at its best with a soft brush on rice paper, which bleeds along its fibres and gives strokes their soft edges. Bamboo, plum blossom and misty mountains are traditional subjects for a reason. They reward confident single strokes.
India ink
India ink is the classic black for pen and brush in the Western tradition. It is the ink comic inkers, illustrators and architects have used for generations. In Easel it pairs naturally with the dip pens, technical pens and fineliners. Use it on smooth papers or card for crisp black line art.
Walnut ink
Walnut ink is a warm brown made, in the real world, from walnut husks. It gives drawings a soft, old fashioned feel, like a page from an old sketchbook. It is lovely for outdoor sketches, figure studies and anything that would look harsh in pure black. Try it with a reed pen or a brush on cream or toned paper.
Acrylic ink
Acrylic ink is the modern one, known for bright colour and a fluid consistency. It suits illustration and mixed media work where you want strong colour that flows like ink. Combine it with pens for line and colour in one session.
The ink wash
Ink wash was in Easel from the start, alongside gouache, acrylic and oil. Like the other wet media it has Water and Thickness settings, so you can thin it to a pale grey wash or keep it strong. It is the tool for tonal studies: block in shadows over a pencil or pen drawing, then layer darker washes where you need depth.
Which ink for which job
A rough rule helps. Brush painting in the East Asian manner wants sumi on rice paper. Crisp line art wants India ink on smooth paper. Warm sketches want walnut. Bright illustration wants acrylic ink. Tonal studies want the ink wash.
The commonest mistake is reaching for pure black for everything. A drawing in walnut or a pale sumi grey can feel softer and more alive. Another is using a very absorbent paper with a fine pen and then fighting the spread. Choose the surface with the ink, and Easel by Zaweba will do the rest.