Watercolor painting has a reputation for being unforgiving, but there are several different ways to fix mistakes in watercolor, make changes, or even to incorporate mistakes into your painting if you can accept some as "happy accidents." You can blot paint up while it is still damp, lift out paint once it has dried, scrape paint off using a razor or fine sandpaper, wash it out under a fine stream of water or under the faucet, or even "erase" it using a Magic Eraser. And if so inspired, you can go into your piece with other media to cover up less desirable areas and turn it into a mixed-media creation.
Firstly, it is important to be aware that some colors have a greater staining power and thus are more permanent than others. For example, alizarin crimson, Winsor blue, sap green, hookers green, and phthalocyanine blue act more like dyes; they stain the paper and are harder to remove completely through traditional means. The Magic Eraser is more effective, though.
You might also choose to avoid these colors by making substitutes using non-staining colors, such as mixing ultramarine blue and cadmium yellow to make green instead of using one of the staining greens.
Also, some papers absorb the paint more, making it harder to lift out the colors when dry. Others, such as Bockingford, Saunders, and Cotman papers, make it easier to lift out colors. Experiment with a few papers of your own to see what works best for you.
Always have a tissue, sponge, soft cloth, and/or blotting paper handy. Watercolor is a fluid medium that, depending on the technique and amount of water used, has an element of uncontrollability and spontaneity about it, making unwanted puddles or drips of water and color a reality. Having something handy with which to immediately blot the offending drip or puddle will make the process go very smoothly. It will also help you keep colors from flooding into one another if you happen to use too much water.
Be sure to blot the paper and lift off, rather than scrub. You don't want to leave pieces of lint or torn tissue on your watercolor paper that will be hard to clean up. Blotting up with a soft cloth or tissue is also a technique that can be used creatively to produce cloud shapes or other organic shapes in a wet wash. A dry brush can be used across the sky for a streaky cloud effect.
Natural sponges will give different effects and textures than will synthetic cellulose sponges. Both are useful for blotting.
For lifting out large areas of color, you can use a large flat piece of paper towel, or a large clean synthetic cellulose sponge you would use in the kitchen, or a piece of blotting paper laid flat. For smaller areas of color, fold or crumple a tissue any way that is most effective, or use a corner of the blotting paper to soak up a small unwanted drop of color.
Blotting paper is thicker than tissue and can be used more than once. In addition to fixing mistakes in a painting, it can also be used creatively to make cloud shapes or simulate the texture of stones, for example.
It is essentially the same thing as good quality watercolor paper (pure rag or linen without any wood fibers in it), although it is more absorbent since it does not have internal sizing like watercolor paper does. Another name for blotting paper is bibulous paper, which scientists use to blot drops of moisture when preparing slides in the lab.
Q-tips, also called cotton swabs by some, can be used to blot up very small drops of color as well.
A method for lifting out color that is still wet or damp is to blot it gently with a soft tissue, sponge, or paper towel. What you use to blot the color will influence the shape and texture of the area that is lifted out.
In addition to fixing mistakes, lifting out wet color with a soft tissue, dry brush, or dry sponge is a technique used to create clouds and to create textural areas such as foliage in a painting.
You can also use a dry brush or q-tip back and forth over a damp area to try to wick up and absorb still more of the paint and moisture. If you've lifted out all you can while damp, let the paint dry completely. You can use a hair dryer on warm to hasten the drying.
When the painting is dry, you may decide that some areas are too dark, or that you neglected to leave areas of white for highlights and need to bring those back, or that some edges need to be softened. There are several things that you can do achieve this.
You can use a damp sponge, brush, or q-tip to rub an area gently and lift out the paint little by little, blotting it with a dry soft cloth or tissue as you repeat the process. A q-tip is very useful since it has cotton on both sides of the stick, one that can be used damp to lift off color, and one that can be used dry to blot the color that has been lifted out. A damp bristle brush can be used on thicker paper to work color out of larger areas as well.
If an edge is too hard, you can soften it by rubbing it with a damp q-tip or brushing it with a damp brush. The same applies to a break in tone—an area that has been painted in a color and shows a sharp line or discontinuity in color when another layer (a glaze) has been painted over it. Lifting out dry color can soften color and create gentle gradations between colors or values.
If there is a larger area that you want to rinse off, you can use a spray bottle with a direct stream and spray the area repeatedly, blotting the water with a tissue, soft cloth, or paper towel. Use the painter's tape or artist's tape to mask off and protect the area that you want to keep.
If the whole painting is a loss, and you've painted it on good thick watercolor paper such as a 140 lb paper or heavier, you can hold it under a stream of cold running water from the faucet or submerge it in cold water in the sink while using a clean sponge to wipe off the paint. Dry it flat and blot it dry and then dry it completely with a warm hairdryer. While you won't succeed in completely bringing back the white of your paper due to the staining of the watercolor pigments, it can be close enough to use for another watercolor painting or at least a mixed-media piece.
Little specks of paint or small blots that find their way accidentally onto your paper can easily be removed by gently scraping with the side of a razor blade or X-acto knife. It is important that you are painting on a heavy-weight paper, at least 140 lb paper, because light-weight papers will easily be torn.
Fine sandpaper can be rubbed gently on the surface and will pick up the top layer of color and lighten it. Sandpaper can also be used to smooth down paper that has become frayed due to being overworked.
Opaque white gouache paint can be used to cover up mistakes, and watercolor can be painted over it. This technique is sometimes frowned upon by watercolor purists, though, and the area might be noticeable. Also, it is more difficult to cover up a dark color completely. However, it is very useful for bringing small highlight details into your painting, such as in eyes.
Chinese White is commonly used by watercolorists but is more transparent because it is made from zinc. It is good for lightening areas and for more subtle highlights.
Mr. Clean Magic Eraser is an amazing cleaning product that looks like a white sponge and that when moistened is a stable polymer abrasive that acts like ultra-fine sandpaper to remove stains, dirt, grime, and even paint pigment from in between the fibers of paper! Be sure to get the "Original" brand, because later versions have additional chemical cleaners in them that aren't good for your paper or painting. The original sponge, though works purely physically. When damp, it easily lifts the watercolor paint from the surface enabling you to go back in and repaint the area you've "erased." You can cut the Magic Eraser to any size you need.
Mask off the area of the painting you want to erase, making sure the edges are secure where you are erasing so water doesn't seep under them and ruin the part of the painting you want to protect. Then rub the dampened Magic Eraser over the area to be erased, rinsing out the Eraser repeatedly in the process to drain out the color. Pat the area dry and repeat the process until satisfied with the results.
Interestingly, this is the same material, melamine foam, invented about twenty years ago, that is also used for soundproofing and insulation since it is lightweight and flame retarding.
Watercolor is a transparent medium that is meant to be painted in layers. Colors can be modified by subsequent layers of carefully chosen color (you don't want to add too many layers for fear of losing the transparency of watercolor, muddying the colors, or degrading the paper). However, while you normally paint from lightest to darkest colors, it is possible to change the hue of a darker color by adding a lighter color over it — for example, yellow over a red, or over a blue — in which case it will warm both colors, turning the red more orange and the blue more green, creating secondary colors.
If you have muddied your colors by adding too many layers of paint, the paper is starting to fray a bit from being overworked, or you can't lift out as much color from the paper as you would like, you have many options for combining other media with your watercolor.
Gouache paint is an opaque water-based paint that can easily be mixed with watercolor. It dries to a matte finish and can cover up areas that are problematic.
Acrylic is another water-based media that is very versatile and can be used over watercolor. Used thinly, it can be used like a watercolor in glazes of luminescent color, and since it is a plastic polymer it has the advantage of not becoming activated when wet, keeping the colors separate and pure. It can also be used thickly and opaquely, and can completely cover a problematic area.
Watercolors can also successfully and easily be combined with good quality colored pencils, both regular or water-soluble such as Prismacolor, ink, and soft pastel.
Oil pastel can be used over watercolor, and watercolor can be painted over oil pastel which will work as a resist to the watercolor.
One of the nice things about working on paper is that, when all else fails, you can cut off the part of the painting that isn't working and still have a painting that you're proud to have done!
Harper, Sally, editor, The Watercolor Artist's Handbook, Barron's Educational Series, Quantum Publishing Ltd, Hauppage, New York, 2003, p. 62.