A In proportional spacing, the tightening of space between letters to create a visually appealing flow to the text.
B The analysis of a picture using techniques that can identify shades, colors, and relationships that cannot be perceived by the human eye.
C Changing or improving graphics images, either interactively using a paint program or by using software routines that alter contrast, smooth lines, or filter out unwanted data.
D Trimming or masking of photos, graphics, drawings, or illustrations.