Things You'll Need
Titanium white paint
Even the most experienced and cautious artists make mistakes from time to time. If you're working with acrylic paints and notice a mistake after the paint has dried, there is a technique you can use to mask and repair the mistake without having to start your painting over again. This technique will essentially "white out" your mistake so you can fix the acrylic paints and save yourself the time and energy of starting the artwork over again.
Wipe the area of the painting you want to fix with a small amount of denatured alcohol to reduce the buildup of acrylic paint. Use a clean, dry paper towel to remove as much of the paint buildup as possible.
Sand down the painted area softly to remove any unwanted texture from the painting. If you like the texture, you can skip this step.
Wipe the dust off the painting with a slightly damp cloth.
Paint the titanium white paint over the dry acrylic paints you want to cover and allow it to dry. Repeat this step if you need to achieve a higher level of coverage.
Paint over the titanium white with your acrylic paints to repair the painting you are working on.
If the canvas you're painting isn't pure white, add a dab of color to your titanium white to mask the error more thoroughly.