Layers are simultaneous, over–
lapping components of an image
or sequence. They are at work in
countless media software programs,
from Photoshop and Illustrator to
audio, video, and animation tools,
where multiple layers of image and
sound (tracks) unfold in time.
Maps use overlapping layers
to associate and separate different
levels of data, allowing each level
to contribute to the whole while
maintaining its own identity.
Printing techniques use multiple
layers of ink to build a single image.
Although the layered archeology
of the printed page or digital file
tends to disappear in the final piece,
experimental work often uncovers
visual possibilities by exposing
layers.