Announcements 4/9/12 Prayer Roy G. Biv - http://www.youtube.com/watch?v=Gf33ueRXMzQ (2:41)

HW 26 due today (but it’s very likely Claira won’t pick it up until Thursday night. Shhh!)

Exam 3 – Should be graded/entered by end of today Final Exam: My apologies, can’t take it in the Testing

Center. Scheduled exam date/time: Tues Apr 17, 3-6 pm. a. Any conflicts?b. Start at 2 pm?c. Some detailed info on the problems…

Foxtrot

Reading Quiz Just kidding

The Goal

Worked Example

X = Y = Z =

Normalize (because “color” should not depend on overall intensity) x = y = z =

xyY

Another Worked Example

What is (x,y) for a delta function at 560 nm?

My estimates:X = 0.59Y = 0.98Z = 0

x = .38y = .62

Do that for every wavelength the “locus” curve

Chromaticity DiagramThings to observe The locus

Example: 560 nm (0.38, 0.62)

The white point = (0.33, 0.33)

Basic color mixing (blue + green = cyan, etc.)

“Line of purples” Linearity: more

advanced combining colors

Complementary colors (can mix to get white)

sRGB

“blue” = (0.15, 0.06)

“red” = (0.65, 0.33)

“green” = (0.30, 0.60)

(If xyY is specified, must first transform to XYZ)

sRGB

“blue” = (0.15, 0.06)

“red” = (0.65, 0.33)

“green” = (0.30, 0.60)

Mixing three sources: triangle

“Gamut”

On the advantages of monochromatic sources

“green” = (0.30, 0.60)

“red” = (0.65, 0.33)

“blue” = (0.15, 0.06)

What’s the Color of Blackbody Radiation?

Wikipedia “Color Temperature”

K 5000K 2000K 1000K

The Sun

The Sun

Color of the Sun?

The Sun

“Stop It”

For a given (x,y) point Dominant color

(hue), D

Saturation (purity), P

Complement color, C

What about this point?

Summary: Ways to Specify Color

R,G,B (original color matching functions) X,Y,Z x,y,Y hue, saturation, Y (“hue, brightness,

saturation”) sRGB R,G,B coordinates (if in sRGB gamut)

That’s All, Folks