his is a very complicated painting technique to execute at home as a hobby, and it suggests a certain mastery of materials, drawing and colour's theory.
In this chapter I'll explain a modern technique to realize works which, using languange indulgence, I call "Frescoes" in the sense that they seem Frescoes.
Let me explain better: this technique consent you to copy, take as a starting point from ancient frescoes and obtain valuable results and sometimes comparable to originals, without passing through the traditional work sequence necessary to paint a true fresco.
This technique is very much used in scenography to make the teatral set.
The first thing to realize is the wall of course.
Ancient frescoes from which taking as a start, as we can see them now, are not painted over a wall perfectly smoothed, quite often the plaster is flaking or cracked in many places and you can see the material below.
If we want to realize something similar, we'll have to simulate this kind of non-uniform surface, with scraping, cracking.
So we need two products:
Acrylic plaster is a product used by masons and painters for mattering facing of a wall, when ashlar-work and spatuliform effects are desired.
It's an acrylic soluble in water material, which can be laid down with a trowel or a spatula; it can be laid either on walls or on wooden tablet, without altering its phisics features. You can find it in paint shops or in big bricolage centers, where it is sold in big tanks, like water paints for walls...
I use wooden tablets about 7 o 8 mm thick, because they are very practical to move and I can lay them anywhere in the various moments of the work.
This first moment of work is very mess-making, so I suggest you to lay a large plastic piece of canvas and work in the garage.
Here is how it appears once it has dried. The cracking you can see in figure is determined by the thikness of the plaster, and by the humidity of the place where you left it dry:
normally a dry room makes wider craking where the plaster is thiker.
It depends on what you are trying to achieve.
It will take 24 hours for the surface to dry, sometimes even more...
Touch the surface gently and sense if it has completely dried, should it be still wet or just humid you'd better wait.
Once the surface has dried, it will be white and so ready for the drawing and the painting.
I suggest you to realize a drawing or a sketch of the subject on a sheet of paper of the exact measures of the tablet.
You will find easy subject to copy or get inspiration in the primitive wall paintings: I've often choosen Minoan frescoes, a culture flourished in the Aegean iselands about 2000 years B.C., or else the Etrurian frescoes... the subjects are simple and are based primarely on the opposition of few complementary colours.
As you become competent in this technique you can try more demanding subjects: such as medieval frescoes or the Renaissance ones... or better something completely yours.
To bring the drawing from the sheet of paper to the wall surface you can use two methods:
I prefer the first method, the filing of pencil is very dirty.
The wall surface we have just realized can be painted with any kind of colour: acrylics, gouache, watercolour, oil...
I prefer painting with acrylics on this surface, because I can obtain either watercolour effects, or covering effects as necessary.
I wouldn't suggest to use gouache or watercolour because every time you wet the surface they may fade.
There isn't a unique precise way of painting on this surface, everyone should feel free to try and find his way.
I can give some suggestions:
Generally, when copying an ancient fresco, I use acrylic much watered down insisting on some areas and on the cracking in order to make the colour seep into the cracks. Once the surface has dried you can use a sandpaper in order to obtain certain effects intentionally faded.
In order to realize the effect of dirt and mould, I use pigments and Siennas, which I melt with an acrylic medium and then spread with the brush or the fingers on the surface where I think it should be.
Paint also the raw wall using the same colour of the background, or a complementary color, as you like.
The smooth areas, which simulate plaster, is never perfectly polished, quite often some ripplings made by the spatula. Use a sand paper on to exalt these effects, which might be interesting.