In printing, ‘Bleed’ is a term used to describe a margin running around an image that is basically surplus to requirements! Bleed areas are intended to be trimmed off to ensure that the printing goes from edge to edge of the surface, leaving no gaps. As it is very difficult to print exactly edge to edge on a surface, images are often required to be slightly larger so that they can be cut down to the correct size afterwards.
A bleed area should also be considered when creating paintings and works that are intended to be displayed in frames, as this margin would allow the full image to sit in a mount or frame without the composition being compromised. The illustration shows a painted area around the main composition that can be trimmed off or hidden behind a mount as required without clipping any of artwork.