Light / Color

Question 1

electromagnetic waves (light)

Answer 1

the eye perceives wavelengths of 400 to 700 nanometers (100,000 to 1,000,000 nuances of color).

Question 2

colors of the spectrum

Answer 2

when white light falls on a glass prism through a narrow crack: red, orange, yellow, green, blue, indigo, violet (the range of visible light).

Question 3

UV vs. IR

Answer 3

UV radiation lies below 380nm, infrared radiation above 780nm (also perceived as heat)

Question 4

retina

Answer 4

a complex layer of nerve endings; on its front surface are light-sensitive sensory cells (receptor cells) that look like rods or cones (sit next to each other and sensitive to light in various areas of spectrum)

Question 5

rods vs. cones

Answer 5

rods: seeing in low light (different shades of light/dark); cones: seeing in daylight and distinguishing colors

Question 6

additive color mixing

Answer 6

red, green, and blue cone receptors. color vision is the superimposition of these 3 colors. If all 3 color receptors are stimulated, the eye will see a white image (red+green=yellow, green+blue=cyan, blue+red=magenta, red+green+blue=white)

Question 7

additive colors

Answer 7

(light colors) created by light addition. all visible colors can be formed with the additive primary colors (RGB). all projected on top of each other: white; all colors missing: black.

Question 8

subtractive color mixing

Answer 8

secondary colors: mixing two additive colors in equal proportion (CMY). the behavior of non-luminous colors, based on the absorption of the colors of the visible light spectrum of white light. (cyan+magenta=blue, magenta+yellow=red, cyan+yellow=green, cyan+magenta+yellow=black)

Question 9

absorption

Answer 9

color impression a viewer gains is created by the light component that meets the surface of object and is reflected, while the remainder is absorbed on impact. the reflected light=color of object (an object that reflects no component colors of sunlight is black; object that reflects all is white)

Question 10

light temperature

Answer 10

if temp of glowing metal body is raised, it radiates different colors of light. light color temps: warm light (3500K), daylight (5500K), cold light (6500K).

Question 11

12-part chromatic circle

Answer 11

Johannes Itten worked on basis of three basic colors: blue, yellow, red. When mixed, produces 12-part circle, with BYR in middle.

Question 12

complementary colors

Answer 12

two colors that lie opposite each other in a chromatic circle (e.g. red/green). mixing 2, produces grey. color combo of 2 complementary is “especially harmonious”

Question 13

Kupper’s color theory

Answer 13

Harald Kuppers bases theory on 6 basic colors: yellow, green, cyan-blue, violet-blue, magenta-red, orange-red arranged in a hexagon. Subtractive mixing (SubMi): primary colors (yellow, magenta-red, cyan-blue) and their interaction with background color white. Additive mixing: primary colors (orange-red, green, violet-blue) and interaction with background color black. Secondary colors formed by mixing 2 primary, tertiary mixing 3.

Question 14

of colors (basic rule)

Answer 14

not more than 4 basic colors should be used

Question 15

RGB values

Answer 15

hexadecimal form (numerals 0-9, letters A-F). hash sign (#) indicates the hexadecimal character of the number that follows.

Question 16

web standards

Answer 16

1st standards developed when computers could only display 256 colors (8 bit), led to development of web-safe palette with 216 colors

Question 17

dithering

Answer 17

a technique that deals with missing colors with a particular pixel arrangement using the available colors (when images with greater color depth then available). avoided by using the standard palette of 216 colors.