Section 7 · Image Construction & Compositing

Selection

Definition

Defining a specific area of pixels to act on, isolating it from the rest of the image. Methods range from geometric (marquee) to tonal (magic wand, color range) to path-based (pen tool).

Why it matters

Selection quality determines composite quality. A rough selection produces halos, hard edges, and fringing no amount of later refinement will fully hide.

Example

Using a path-based selection for a hard-edged manufactured object and an edge-refinement tool for hair or foliage — different subjects demand different methods.

Teaching note

Students default to one tool for everything. Presenting selection as a decision about subject type, rather than a tool to master, is the shift worth engineering.