Can I make an acrylic pour painting digitally?

Acrylic pours are possible in Easel by Zaweba, a free and offline painting studio for Windows, which includes pouring acrylic as a paint and a pour tool with silicone cells. Once the paint is down you tilt the canvas with a dial and the wet paint flows across the surface, much as it does when you lift and turn a real panel.

Acrylic pouring, sometimes called fluid art, is the craft of mixing runny acrylic paint, pouring it onto a surface and tipping the surface so the colours spread and swirl. Silicone oil added to the paint makes cells, the small rounded gaps where one colour breaks through another. It is a popular hobby and also a messy and expensive one, since a single pour can use a lot of paint and you rarely get the same result twice.

How Easel approaches a pour

In most drawing programs a pour effect would be a texture or a filter. In Easel the paint is treated as a liquid on the surface. How much liquid moves depends on its height, the slope from the tilt, its viscosity and the surface tension at dry edges. That means a pour behaves according to how much paint you laid down and how far you tip the canvas, not according to a stamped pattern.

The pour tool lays down a stream of paint, and it can include silicone cells. Pouring acrylic is the paint meant for it. Both run when the canvas is tilted, alongside drip and flick for spatters and thrown lines.

The tilt dial sets the angle and the direction. Its angle grows with the square of the distance from the centre, so gentle slopes are easy to find, and Ctrl+0 brings the canvas back to flat.

Colours that blend as paint does

A big part of a pour is what happens where colours meet. Easel mixes colour with the Kubelka-Munk model, written by Zaweba, so blue and yellow make green instead of a muddy grey, wet or dry. Where two pours overlap you get the mix a pigment painter would expect, and thin layers stack as glazes.

You can choose colours from paint sets named by colour, pick any colour from a colour picker, or keep favourites in My colours. Squeezing paint onto the physical palette and mixing it with the knife is a nice way to prepare custom colours before you pour.

Things to try

Change the surface. Easel has 37, from primed canvas and gessoed panel to glazed tile, aluminium and glass. A slick surface such as glass or tile wipes clean, so you can experiment and start again without making a new picture.

Change the timing. The drying speed slider runs from a quarter of normal to four times faster. A slow setting gives you longer to tip the canvas back and forth. When a pour looks right, Dry now locks it in place so the tilt can no longer move it, and you can add a second pour on top.

Use undo. It keeps 80 steps by default and includes tilt runs and drying, so a pour that ran off the edge can be pulled back.

What a digital pour is good for

A digital pour will not replace the pleasure of real paint, and nobody is suggesting it should. It is useful for testing colour combinations before you buy paint, trying out an idea for a large panel, or simply enjoying the process without the cleanup. Easel keeps a frame after every stroke and while paint is moving, so you can export the whole pour as a WebM video or a web page, and a saved .zeasel file keeps wet paint wet if you stop halfway.

A decent graphics card helps, because the paint is computed on the GPU. On a basic chip, the paint flows a little slower rather than your strokes lagging.

For anyone curious about fluid art, it is an easy and free way to see what happens when colours run together, and to learn how much tilt a pour can take before it slides off the edge.