noun ( pl. -ti |-ti|)
literally ‘scratched away’; a form of decoration made by scratching through a surface to reveal a lower layer of a contrasting color, typically done in plaster or stucco on walls, or in slip on ceramics before firing.
This technique is pretty much like scraperboard work…or those oil pastel drawings you made in primary school art class that you covered with a thick black poster paint, and then scraped back to reveal the colors…with the advantage of being fully smudge and waterproof once dry, because you only use acrylic paints, which makes it a great technique for the art journal.
Start by painting your page with the background colors. You can paint it solidly in one color of acrylics, as I hurriedly did today for this post, or you can execute an actual design—shapes, letters, whatever—in blocks of solid color.
N.B. Remember that when you cover the background with another color to start the sgraffito, the background color will only be seen in the lines you have scratched out. So if you want a pink lily, for example, with fine black lines, you would paint a black lily, first, and then cover it all up with a very opaque pink, and then scratch lines to reveal the black underneath.
When the acrylic is dry, give the page a single coat of gloss or semi-gloss acrylic medium. This seals one color from the next, keeping the layers of different colors from sticking to each other, and so keeps the colors and lines distinct.
Take the color of your next layer, and mix it with retarder medium. Don’t use any water, just the medium, and try to use a paint to medium ratio of 2:1…too much retarder medium and your paint will take forever to dry. Also, it will sit in a wet puddle that is no good for scratching because every time you draw a line through it the wet paint will simply flow in to fill the line again. You want the paint smooth but not runny.
Fill in the shape, or letters, or whatever that you’ve drawn. Don’t do the whole page at once…remember that even with retarder, the thin film of paint will start to dry, and if the shape is so big that it takes you a long time to scratch your designs into it, parts of it may be dry before you get to them. Scratching only really works if the paint is still wet. I work on patches the size of a playing card, scrape my lines into it, then paint the next patch, scrape into that, and so on.
I didn’t have a design planned,so I just kind of doodled this rather underwhelming shape: yet another tentacled creature…every time I try to paint something spontaneously I end up with tentacles. Damn limited imagination. Anyway.
Experiment with scratching tools. From top to bottom are a thin brass rod, a sculpting tool with a soft rubber cone on the tip (I think polymer clay artists use these things?), and the wrong end of a thin paintbrush. Personally I find the rubber-tipped tool too yielding…the very end of the cone tends to wiggle, but you may like that. I prefer the metal rod and the paintbrush…firm sticks that draw consistent lines, each of a definite weight. Find what you like.
Keep a wad of tissue in your other hand, and start scratching your design into the wet paint. Every inch or so, wipe the tip of your tool off on the tissue paper, as a glob of wet paint will collect there. The term “scratching” here isn’t quite accurate…it implies more force than necessary. There’s no need to bear down or tear the paint and paper beneath. If the paint hasn’t dried yet, it’s like drawing in butter. If the paint has dried, you can still revive it with a tiny dab of retarder from a small brush. Spread that dab of retarder around the dry area, wait a few seconds, and try again.
The rounded tip of a paintbrush makes good dots…hold the brush vertically and rotate the handle between your fingers, rather than try and ‘gouge’ the dot out from one direction. It makes nice round dimples (albeit small ones)
If you have made your paint too wet and runny—with either water or retarder—you will know it right away, because the paint will form wet patches, and scratching into it will not leave behind a clean path, but the liquid paint will creep back into the lines you scratched, which is what happened in this toxic green speech bubble I painted next. Wait a bit for the paint to dry a little bit or, if you used too much retarder and it looks like the paint won’t dry for hours, blot it up with paper towel, maybe a slightly moistened one (the acrylic gloss medium will protect the background layer) and paint the shape in again with the right consistency of paint.
And that’s it. Nothing special, really, but it produces a nice effect of its own, distinct from painting fine lines onto a background with a brush or mapping pen. It was often used by the old masters in their oil paintings to hint at, without actually detailing, the intricate lines of lacework or leafy shrubbery. It allows your drawn line to variegate from color to color, too…just paint the background with rainbows or whatever, before covering up and scratching through.
I wish I’d given more thought to what I was going to draw for this post…this tentacled thing has turned out pretty fugly. Hopefully you see the potential of the technique without being put off by Squid Ugly, here.