Color SpacesCNM 190, Spring 2010
Jeremy Huddleston & Dan Garcia
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Terms (1)
Chromaticity
Hue, “base color”
Saturation, “tint”
Brightness, Luminance, Value, “shade”
Complimentary -- add to white
Gamut -- encodable subset
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Spectral Analysis
image ref: http://thefiberopticstore.com/purchase/LED/specs/index.htm 3
CIE XYZ (1)
Commission Internationale de l’Eclairage (1931)
2D slice with Luminance = 1
Border consists of the spectral primaries
image ref: http://en.wikipedia.org/wiki/CIE_1931_color_space4
CIE XYZ (2)
Gamut for 3 primaries (R,G,B) is their triangle
Other colors would require “subtraction”
Color = rR + gG + bB
image ref: http://en.wikipedia.org/wiki/CIE_1931_color_space5
CIE XYZ (3)Choose 3 imaginary primaries (X, Y, Z)
Full Gamut
C = XX + YY + ZZ
L = X + Y + Z
x = X / Ly = Y / Lz = Z / Lx + y + z = 1
image ref: http://en.wikipedia.org/wiki/CIE_1931_color_space
X=Cr , Y=Cg, Z=Cb
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CIE XYZ (4)
Anorher Typical Encoding: CIE xyY
X = xY / y
Y = Y
Z = zY / yZ = (1 - x - y)Y / y
image ref: http://en.wikipedia.org/wiki/CIE_1931_color_space
X=Cr , Y=Cg, Z=Cb
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CIE XYZ (5)
ref: SIGGRAPH ET 2005, http://www.youtube.com/watch?v=x0-qoXOCOow8
sRGB (1)
Color = rR + gG + bB
White point = D65
“White Balance” is a linear transformation called the Von Kries transform
image ref: http://en.wikipedia.org/wiki/SRGB9
sRGB (2)
Primary Colors: RGB
Secondary Colors: CMY
Complimentary Colors: RC GM BY
image ref: http://en.wikipedia.org/wiki/SRGB10
HSV, HSL (1)
Hue: “base color”
Saturation: “purity”
Value: Luminance
image ref: Apple Keynote Screenshot, http://en.wikipedia.org/wiki/HSL_and_HSV
HSV Slice: V=1HSV Cone
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HSV, HSL (2)
Hue: “base color”
Saturation: “purity”
Lightness
image ref: http://en.wikipedia.org/wiki/HSL_and_HSV
HSL Bicone
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HSV, HSL (3)
image ref: http://en.wikipedia.org/wiki/HSL_and_HSV13
Terms (2)
Additive Color Space (light)
Subtractive Color Space (pigments)
Tone
Shade -- adding black -- “value”
Tint -- adding white -- “saturation”
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CMYK (1)
Subtractive
Primary Colors: CMY
Secondary Colors: RGB
Why do we need K?
image ref: http://en.wikipedia.org/wiki/CMYK15
CMYK (2)
image ref: http://en.wikipedia.org/wiki/CMYK
Black slightly increases our gamut
Black saves us $$$ (one ink pass rather than 3)
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Review
Spectral Graphs
CIE XYZ
HSV
HSL
sRGB
CMYK
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ExtrasHomework
BSpace
Colored Frames on Monday
Still looking for a reader
Color Combination Aesthetics
http://kuler.adobe.com
http://www.worqx.com/color/combinations.htm
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