A dropshadow is the visual effect consisting of a drawing elements that looks like the shadow of an object, giving the impression that the object is raised above the objects behind it. It’s used to add a sense of depth to a visual but it’s first of all an effect, not a style.
Drop-shadow is not an obligatary style element and it’s even discouraged (but not forbidden). The rationale behind this is that dropshadow is an executional variant and subject to the display material and resolution.
Many tools have their own way of implementing drop shadows:
- Print drop-shadows may be realized using a raster
- Digital dropshadows can be transparent variants of a dark or gray box.
Because drop shadows are inherently effect based and interact with the background, the dropshadow itself has no color but hints at the absence of light, not colour.
Drop-shadows are discouraged but it might, if not managed properly, create unforeseen effects such as aliasing and require a file format that preserves transparency.
Most legacy image formats do not support transparency.
- Dropshadow is not a style element
- Dropshadow is left to the discretion of the designer
- Dropshadow is, at best, an after-effect applied to final design.