Digital image filtering
From The Glossary of Digital Photography
A process of applying filtering techniques in software applications to change a digital image. Well-known applications of this are the filters available in Photoshop. Originally, digital image filtering was used to correct an image by sharpening it, reducing dust or artifacts, or similar tasks. Now digital image filtering is done for creative purposes as well. Some of the filtering techniques include artistic ones such as colored pencil, dry brush, film grain, fresco, neon glow, palette knife, plastic wrap, rough pastels, smudge stick, sponge, and watercolor. Various kinds of brush strokes and distortions can be applied. There are sketching techniques and textures as well. All of these effects can easily be seen by using Photoshop's filter gallery.
