What is a layer?
The best way to understand layers is to think of each layer
as a sheet of acetate, as used for overhead projectors. Picture a
clear page, with parts of the page information on each page. In the
sample at the left, note which object is in front of the next and
then note the stacking order as represented in the exploded layers
representation. The Photoshop Layers palette for this design is
It is best to place every new element, or addition to an
element, on its own layer. You can always merge (combine) layers,
and it is much safer and faster to build each element a layer at a
time. Once you are satisfied with the look, you can then combine
the elements that make up that object. As an example: If you wish
to make a square with an outline, build your square first, and then
add your outline on a new layer. As long as the layers are
separate, you can easily change either the fill or the stroke
color, and the stroke width.
Building in layers will seem awkward in the beginning, since it
is easy to gather a significant number of layers. Soon though, you
will develop an instinct for when to combine and link layers to
make the layers palette less cumbersome.