Optical effectOptical effects
are those film
effects that are created entirely through an optical process using film, light, shadow, lenses and/or chemical processes. Examples are film titles, fades, dissolves, wipes, blow ups, skip frames, bluescreen
, compositing, double exposures, zooms/pans and many more special effects
All of these things can now be done electronically and/or digitally, but they were originally created in an analog environment.