How to paint a fresco digitally

To paint a fresco digitally, open Easel by Zaweba, a free painting studio for Windows, choose the wet plaster surface and paint with lime-water pigment. That pairing follows the true fresco method, where pigment mixed with water is brushed onto fresh lime plaster. Both were added in Easel version 1.1.

Fresco is how the great wall paintings of Italian churches and palaces were made. In true fresco, often called buon fresco, the painter applies pigment in water to plaster that is still wet. As the plaster sets, the colour becomes part of the wall. It is a demanding method because you can only paint the patch of plaster laid that day, and corrections are hard once it has set.

Start with a drawing

Easel and a sense of the composition. Fresco painters always worked from a drawing, so it helps to have one ready. Easel lets you place a reference photo beside the canvas, or as a faint tracing guide, and it is never merged into the painting. A tracing paper or acetate sheet over the picture can hold guide lines, and Ctrl+H shows or hides it.

Plaster, pigment and the first layers

Start a new picture at the size you want. You can choose A sizes, squares or custom millimetres at 72 to 300 DPI. For a mural-shaped design, custom millimetres let you match the proportions of a wall.

Choose wet plaster as the surface. It is one of the 37 surfaces, alongside more familiar ones such as canvas and watercolour paper.

Choose lime-water pigment as the paint. This is the fresco paint, pigment in lime water rather than in oil or gum.

Lay in the drawing on the tracing sheet, then paint the large areas first. Fresco colour tends to be soft and luminous, so build up gradually with thin layers.

Work patch by patch. Even though the digital plaster will not set overnight the way real plaster does, thinking in sections helps you keep the colour consistent, just as fresco painters did.

Colour and value on a wall

Mix your colours on the palette before you paint. Easel's physical palette lets you squeeze paint out, mix with the knife and load the brush from the mix. Colour mixes like pigment, using the Kubelka-Munk model, and thin layers stack as glazes.

Use soft brushes. Round, filbert and mop brushes are good for the broad, gentle passages that fresco is known for. A rigger is handy for fine lines.

Check the values. The values view shows the picture in greyscale and never changes the painting. Large wall paintings must read from a distance, and step back shows the picture from a distance too.

Mind the drying. The drying speed slider runs from 0.25 to 4 times, and Dry now locks wet paint in place. Humidity and warmth, set in the studio climate, also change how paint behaves.

Ageing a finished fresco

Old frescoes have faded and softened. Easel's Age the picture tool simulates time on a painting, for instance fading fugitive colours and cracking old oil. Try it on a copy if you want a weathered look, and keep the fresh version too.

Other ways to get a wall look

If you want a modern wall painting rather than a classical fresco, Easel has brick wall and concrete surfaces, household emulsion as a paint, and spray paint with nozzle size, distance and pressure. For an old master look on panel, egg tempera and casein are also among the paints added in version 1.1.

Save as .zeasel to keep the work, wet paint and all, or export PNG, JPEG or TIFF at 1x or 2x.