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fourteen. contrast 1: shadow and light. (Some) components of an image. Parameters (of pixels and regions) Color: hue, saturation, value (brightness) Texture Size Weight Contrast Variations in a parameter Form Line Plane Volume Shape Composition Placement
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fourteen contrast 1: shadow and light
(Some) components of an image • Parameters (of pixels and regions) • Color: hue, saturation, value (brightness) • Texture • Size • Weight • Contrast • Variations in a parameter • Form • Line • Plane • Volume • Shape • Composition • Placement • Balance, proportion, scale relationships • Repetition/change
Contrast • Defines objects • Directs attention • Local contrast draws attention • Establishes mood • Wide range/narrow range • More contrast generally more dramatic
Chiaroscuro:Contrast in value • Most important source of information for the visual system • Used to • Separate figure from ground • Direct attention • Establish shape • Establish depth • Set mood • Manipulated through control of • Shape • Pigmentation • Lighting Fritz Lang, M (German, 1931)
Haloing Separates figure from ground Friedl Dicker, Light and dark study, c. 1920
Rim lighting John Lasseter, Toy Story (USA, 1995) key fill rim Used to emphasize outline of an object in shadow • Key light leaves left edge of character in shadow • Can’t make out object boundaries • Spooky (Tom Hanks isn’t supposed to be spooky) • Weak rim light brings up contrast at object boundary • Tom Hanks safely de-spooked
Directing attention • Eye is drawn toward • Bright areas • Areas of high contrast
Directing attention Caravaggio The Calling of St. Matthew, C. 1597 Rembrandt, The Night Watch, c. 1624
Modeling • Pictorial techniques to bring out object shape • Chiaroscuro very important • Point-lights generate • strong shadows • Highlights Carvaggio, Incredulity of St. Thomas
Shape from shading • We compute surface curvature from intensity gradients • Bias to assume light source is above the head
Modeling with lighting • Key light • Offset from camera • Mood, modeling • Fill light • Fills in rest of scene • Keeps shadows under control • Others • Back light, rim light, …
Photography with direct flash is evil • Direct flash has the light source at the lens, pointing at the subject • Flattens image • Highlights are in the “wrong” place • Bounce flash points the light at the ceiling or some other surface
Mood • Contrast connotes emotional intensity • Danger • Excitement • Example: film noir • Washed-out scenes connote dreariness • Boris Karloff effect
Mood Georges de la tour , The Repentant Magdalene, C. 1640 Georges de la tour, St. Sebastian, C. 1650
film noir one-stop shopping for examples of high-key dramatic lighting
the 1970s one-stop shopping for examples of low-key ennui lighting
Fantasy/SF more high-key lighting and chiaroscuro