The final touch to a finished work of art is the artist's signature. For collectors, it is one of the first things they try to identify on a painting. And, for the artist, signing a painting usually means their work is complete. Signatures are typically found in the bottom corner of paintings, though in more contemporary works, artists may incorporate their name into the actual painting as part of the composition.
Traditionally, artists sign their paintings in whatever medium they used to create the painting. For acrylic paintings, acrylic or oil paint can be used. For oil paintings, oil is the best choice so that it will adhere to the surface.
Sable brushes or synthetic sable are the easiest to work with to sign paintings. Synthetic sable or hogs hair bristle brushes work best for applying acrylic paint. Decide how large the signature will be, and choose an appropriate-sized brush so that you can paint the width of the text in one brushstroke. The larger the work of art, the larger the signature should be, so that it fits in with the painting. If you have created a mural, consider using a 3-inch house paint brush for your signature.
It is worthwhile testing out your signature on newspaper prior to signing the painting to make certain you have selected the correct brush size.
For the paint to create a similar fluid illusion to signing a document on paper, artists oftentimes will use a medium mixed with the paint to help applying the paint in a smooth manner. Water is the best vehicle to add into acrylic paint to help with flow while applying letters to canvas. Oil paint requires either turpentine or linseed oil mixed into the paint for an even flow that is easily controlled. Higher-quality oil paints may not require any additional mediums if the texture of the paint is already easy to manipulate.