1	Efficient Color for Efficient Web Applications Victor Ostromoukhov Université de Montréal
2	Color is one of the most effective visual attributes for coding information in displays and is capable, when used correctly, of achieving powerful and memorable effects
3	A little color can be more effective than a lot
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7	Outline Introduction: What Is Color? Milestones in Understanding Color Artistic Approach Scientific Approach Perceptual Phenomena Studied in Psychology & Neuroscience … And by Artists Conclusions
8	What is Color?
9	What is Color?
10	What is Color?
11	What is Color?
12	What is Color?
13	What and Where Subsystems
14	Outline Introduction: What Is Color? Milestones in Understanding Color Artistic Approach Perceptual Phenomena Studied in Psychology & Neuroscience … And by Artists Conclusions
15	Two Great Western Traditions
16	Rational Tradition
17	Mystic (Artistic, Emotional) Tradition
18	Plato c. 380 BC Inverse physical model: visual rays are emitted from the eye Two basic colors: white extends visual rays black is its opposite Other colors are derivative: "by virtue of the ray of blended fire gleaming through the moisture, a color similar to that of blood is created"
19	Newton 1672 Belongs to Both Great Traditions Rational Tradition: Discovery of Truly Primary Colors Theory if Light Color Mixture Pythagorean Tradition: Color is a Manifestation of the Harmony of the Celestial Spheres Studied Relations between Colors and Music
20	Lambert 1760 Color pyramid Base color triangle Tertiary colors Basis for mathematical approach to colorimetry Intended for printers, dyers and craftsmen
21	Runge 1803 Theorist and Romantic Painter
22	Goethe 1810 Circular diagram: primary colors (red, blue and yellow) alternate with secondary colors (orange, violet and green) Exerted huge influence on generations of artists, scientists and philosophers
23	Goethe 1810 Related aesthetic and emotional values of colors: "powerful", "gentle" and "radiant"
24	Chevreul 1839 Great Influence on XIX century painters: Delacroix, Impressionists, Post-Impressionists, Pointillists
25	Maxwell 1867 Origins of modern quantitative color measurement (Colorimetry) Experiences with Color Mixtures Psychological explanation of visual phenomena
26	von Helmholtz 1859: Trichromatic color theory
27	Hering 1874 Father of the opponent process color theory Focus on psychological interpretation of colors
28	Munsell 1905 System of visually uniform distribution of color patches Ancestor of CIE-LAB and CIE-LUV color spaces
29	Retinal Neural Interconnection 1900s
30	Neural Codes
31	Milestones Discovery of complex receptive fields in the visual cortex Neural mechanisms of visual information processing
32	Nowdays Color Appearance Models: Predict the appearance of a color depending on Objective stimulus Surrounding, context Exploration Of Higher-Level Perception and Cognition, Based on Modern Non-Invasive Scanning Techniques (MRI)
33	Outline Introduction: What Is Color? Milestones in Understanding Color Artistic Approach Scientific Approach Perceptual Phenomena Studied in Psychology & Neuroscience … And by Artists Conclusions
34	Antiquity
35	Middle Age Fine Control of the Process Notions of Optical Color Mixture Mastery of Color Contrast
36	Leonardo 1510 Distinction between primary and secondary colors Effects of aerial attenuation of colors Simultaneous contrast
37	Renaissance Masters
38	Breakthrough in Realism circa 1430 (according to Hockney)
39	Rubens beg. of XVII century Mastery of Flesh Colors Glazes, Transparent and Opaque Colors
40	Vermeer mid-XVII century
41	XIX century Romantic Painters: Eugène Delacroix Explicit Usage of Opponent Colors Simultaneous Contrast
42	Impressionism Retinal Image: Painted What They Saw
43	Post-Impressionism Expressive Power of Complementary Colors
44	Pointillism Use of pure colors Reduced palette Additive rather than subtractive mixture
45	Expressionism
46	De Stijl and Bauhaus
47	Post-Modernism
48	Photo-Mosaics, Artistic Halftoning
49	“Layered” pointillism
50	Outline Introduction: What Is Color? Milestones in Understanding Color Artistic Approach Scientific Approach Perceptual Phenomena Studied in Psychology & Neuroscience … And by Artists Conclusions
51	Colorimetry: CIE Color Matching
52	CIE-XYZ Color Space
53	The Colors in the Chromaticity Diagram
54	Perceptually Uniform Space: MacAdam
55	CIE-LAB
56	Gamut Mapping
57	Gamut Mapping Gamut mapping is a morphing of 3D color space according to adopted scheme
58	Color Pickers: HLS
59	Device-Dependent Color
60	Device-Independent Color
61	Outline Introduction: What Is Color? Milestones in Understanding Color Artistic Approach Scientific Approach Perceptual Phenomena Studied in Psychology & Neuroscience … And by Artists Conclusions
62	Perceptual Phenomena Studied in Psychology & Neuroscience Contrast Enhancement (Mach Effect) Simultaneous Color Contrast Chromatic Adaptation Complementary (Opponent) Colors Light Mixture Color Blindness
63	The Mach effect
64	The Cornsweet effect
65	Summing and Subtracting Cone Signals
66	Color opponents wiring Sums for brightness Differences for color opponents
67	Pointillism Haloing, local contrast
68	Negative space
69	Simultaneous Color Contrast
70	Chromatic Adaptation
71	Crispening Increased sensitivity
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73	Anchoring vs. Scaling
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75	After-Image-white
76	After-Image
77	After-Image-white
78	Opponent Colors
79	Light Mixture Mixing two lights in varying proportions produces colors that lie along the straight line between them in color space Mixing three lights in varying proportions produces colors that lie within the triangle they define in color space
80	Physical color mixture Additive Subtractive red, green, blue cyan, magenta, yellow
81	Spreading Optical mix when spatial frequency increases But before fusion frequency Additive mix! (opposed to pigment mix)
82	Color Printing
83	Divisionism
84	Color blindness 8% male (up to 12-20%, according to some estimations), 0.6% female Genetic Dichromate (2% male) One type of cone missing L (protanope) M (deuteranope) S (tritanope) Anomalous trichromat Shifted sensitivity
85	What is Color?
86	Color blindness 8% male (up to 12-20%, according to some estimations), 0.6% female Genetic Dichromate One type of cone missing L (protanope) M (deuteranope) S (tritanope) Anomalous trichromat Shifted sensitivity
87	Color blindness test (Ishihara)
88	Color blindness test (Ishihara)
89	Color blind impressions
90	Web-Safe Palette
91	Safe Web Colors for color-deficient vision
92	Safe Web Colors for color-deficient vision
93	Outline Introduction: What Is Color? Milestones in Understanding Color Artistic Approach Scientific Approach Perceptual Phenomena Studied in Psychology & Neuroscience Perceptual Phenomena Exploied by Artists Conclusions
94	Differential Filtering
95	Differential Filtering
96	Color Shadows
97	Chromatic Adaptation
98	Color Shadows
99	Perception of Space
100	Perception of Space
101	Perception of Depth
102	Perception of Depth
103	Perception of Motion
104	Perception of Motion
105	Chromatic and Achromatic Visual Acuity
106	Chromatic and Achromatic Visual Acuity JPG, MPG Color opponents instead of RGB Compress color more than luminance
107	Conclusions Color vision is a complex process RGB color space is device-dependent Use CIE-LAB as device-independent perceptually uniform color space Take into account Simultaneous contrast Chromatic adaptation and after-image Color spreading and crispening effect Chromatic and achromatic visual acuity Use Web-safe palette for normal vision and protan/deutan palette for anomalous vision
108	Selected Bibliography Colorimetry, Color Science
109	Selected Bibliography Colorimetry, Color Science
110	Selected Bibliography Psychology, Neuroscience
111	Selected Bibliography Psychology, Neuroscience
112	Selected Bibliography Color and Art
113	Selected Bibliography Color and Art
114	Selected Bibliography Color and Art
115	Selected Bibliography Color Blindness
116	Thank You!