If you thought the only end of a paintbrush you should be using is the one with the hairs on it, you need to think again. The ‘other end’ is very useful for the technique called sgraffito.
The term sgraffito comes from the Italian word sgraffire which means (literally) "to scratch." The technique involves scratching through a layer of still-wet paint to reveal what’s underneath, whether this is a dried layer of paint or the white canvas/paper.
Any object that will scratch a line into the paint can be used for sgraffito. The ‘wrong end’ of a brush is perfect. Other possibilities include a fingernail, piece of card, sharp point of a painting knife, a comb, spoon, fork, and a hardened paintbrush.
Don’t limit yourself to scratching a thin line; broad sgraffito with, for example, the edge of a credit card, can also be very effective. If you’re using something sharp, such as a knife, you need to be careful you don’t accidentally cut the support.
And don’t limit yourself to using the technique with just two colors. Once your top layer has dried, you can apply another color on top and scratch through this. Or you could apply a range of colors in your bottom layers so different colors show through in different parts.
The main thing to remember when doing sgraffito with oils or acrylics is that the color you want to show through must be totally dry before you apply the layer of paint you’re going to scratch away. Otherwise, you’ll scratch off both layers.
When the initial color has dried, apply the color you’re going to scratch through. The top layer of paint should not be runny, otherwise, it’ll just run back into the areas you’ve scratched. Either use the paint quite thick, so it holds its form, or let it dry a little before you scratch into it.
Sgraffito is particularly effective with impasto painting, providing another level of texture as well as the contrasting color. If you like having text on a painting, you should try using sgraffito—you may well find it easier than trying to paint on words.
Sgraffito on paper works differently to sgraffito on canvas because the layer of paint is (generally) so thin you’re scratching the paper as well as the paint. Where you scratch or indent the surface of the paper, the wet, top paint will collect in it, rather than revealing the white of the paper. If the paint's beginning to dry, less will flow in.
Using a knife, sharp blade, or sandpaper to scratch the surface of watercolor can be very effective for creating texture, but remember you’ll have ‘damaged’ the surface of the paper and it’ll be very absorbent (porous) if you paint on it again.
If you add a little gum arabic to your watercolors, the paint will have more body and sgraffito marks will be more prominent, or defined.
Sgraffito can be very effective for painting hair, or rather 'drawing back' into the paint to create strands of hair. Depending on what size object you use, you can get marks of varying width, from very thin to represent individual hairs to thick to represent bunches or highlights.
In the example shown here, the colors had gone rather muddy as a result of overmixing them on the paintings. Being in acrylics rather than oils, scraping back right down to the canvas wasn't an option as the lower layers of paint had dried already. But rather than paint over it, sgraffito was used to create the impression of hair, facial features, and the shirt.
The resulting painting isn't a masterpiece, but it does have a great feeling of texture. Imagine how it would look if the color of the hair had been more intense.
If you're painting on a canvas with a relatively coarse grain or weave, for instance, cotton duck canvas, sgraffito can be used very effectively with this. When a layer of paint is dry, you paint over with a new color and while this is still wet use the side of a large painting knife or palette knife to scrape off most of the paint.
The new color will remain in the lower "pockets" of the weave, as the photo shows because the knife doesn't reach into these. If you want to remove more of the color, dab at the painting with the cloth. Use an up-and-down motion rather than moving it from side to side, which will smear the paint across the canvas.
This technique can be used over a whole canvas or merely a small section. A variation is to wipe a painting knife, with only a little paint on it, flat across the canvas so the paint goes only onto the top of the canvas weave.