Reading Assignment #4: quiz next week!

Art 105: Two-Dimensional Design

Professor: Kyle Stevenson

Project 4 vocabulary: Value

Reading: Pipes- Intro to Design, Chapter 6,

The Vocabulary of Value (and using grayscale):

value:  A measure of the relative lightness or darkness of a color, also known as brightness.

tint:  A hue mixed with white.

shade:  A hue mixed with black.

achromatic:  The absence of hue and saturation.  Black, white and the grays in between.

Achromatic grays:  Made from mixing just black and white together with no other color.

contrast:  The value relationship between adjacent areas of light and dark.  The highest contrast of all is black and white.

value pattern:  The shapes that an arrangement of various light and dark value areas in a composition make, independent of any colors used.

value emphasis:  Where a value contrast is used to create a focal point within a composition.

graduated tint:  A continuous change in value with no observable banding..

value contrast:  The relationship between adjacent areas of light and dark colors.  The highest contrast of all is black and white.

mid-tones:  The tints at the center of a chromatic scale, midway between black and white.

low-key values:  A value that has a level of middle gray or darker, tints from middle gray to black.

high-key values:  A value that has a level of middle gray or lighter, tints between the mid-tones and white.

local values:  The relative light and dark of a surface, seen in the real world,  independent of any effect created by the degree of light falling on it.  A smooth rounded object will disperse the light gradually and subtly, whereas light shining on an object with angular surfaces will result in distinct areas of contrasting light and shade..

core shadow:  The dark part of an object, away from and not directly illuminated by the light source.  It is attached to the object, or encompasses a space..

cast shadow:  The dark area projected from an illuminated form onto other objects or the backgroud.

highlight:  The part of an object that, from the viewer’s position, receives the greatest amount of direct light.  The highest value of a modeled form, or a bright distinct dot or area on the surface of a shiny form that accentuates its glossiness.

dynamic range:  The range of pigments from the lightest to the darkest, usually within the range from white to black.

underexposed:  If a photographer decides to adjust a camera to capture the light areas of a scene, then the dark areas will be uniformly black and lacking in detail in the shadows.

overexposed:  When photographers adjust their cameras to capture a dark object against a light background, then the light areas will be bleached out and lacking in detail.

chiaroscuro:  The distribution of light and dark in a picture.  From the Italian chiaro for clear or light and oscuro for obscure or dark.  It has come to refer to the dramatic theatrical compositions of Caravaggio and Rembrandt.

grisaaille:  A monochromatic version of chiaroscuro in shades of gray or a neutral color which imitates the appearance of low-relief sculptures.

sfumato:  Lenordo da Vinci’s shading technique, it is Italian for “smoke”.  A transition of value from light to dark so gradual that the eye cannot detect any distinct tones or boundaries between values.

tenebrism:  A technique of painting, from the Italian word (tenebroso) meaning “obscure,” used by Caravaggio and his followers and characterized by a little bright light and lots of almost black shade.

specular reflection:  A type of reflection that distinguishes shiny glossy surfaces or objects from dull matt ones.

ray tracing:  Computer graphics technique for lighting a scene developed by Turner Whitted.  Every time a ray of light encounters a surface, it divides into three parts: into diffusely reflected light; into specularly reflected light; and into transmitted or refracted light.  Rays are traced back from the viewer, bounced back from the viewer, bounced around the scene, and arrive eventually back at the light source.

radiosity:  Computer graphics technique for lighting a scene globally by calculating the light-energy equilibrium of all the surfaces in an environment, independent of the viewer’s position.