Masking with Tape
Tape is another tool that can be used to mask borders, edges, or straight lines. It’s safest to use artist’s tape, which adheres more loosely than masking tape does and can be removed with less danger of damaging the paper. To mask off straight objects (such as the sides of buildings) or to create straight lines, paint along the edge of the tape; when the tape is removed, you’ll have a perfectly straight edge. When removing the tape, slowly pull the tape off the painting. It’s best to remove the tape while the paint is still slightly damp.
MASKING EDGESYou can use tape to mask off the edges (or border) of your painting area. When you remove the tape, you’ll reveal a clean, white edge. The edge will give you a good idea of what the painting will look like when it’s matted, and the neat edge will make it easier to see and judge your colors.