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Upcoming Classes Thursday, Nov. 29 th Making Color (Visual Arts @ Nexus) Assignment due: * Homework #5 (Visiting the Exploratorium) Tuesday, Dec. 4 th Third set of Oral Presentations Assignment due: * Last term paper or oral presentation Thursday, Dec. 6 th (Last day of class) Making Holograms (Meet in Science Bldg, Room 133) Assignment due: * Homework #7 (Optical Instrument) * Written summary of your MUSE workshop activities
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Upcoming Deadlines Tuesday, December 4 th Third Set of Oral Presentations Third term paper (if not presenting) Thursday, December 18 th Final Exam
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Oral Presentations (III) The following persons will give oral presentations on Tuesday, December 4 th : Remmel, Katherine Sugiura, Ayuka Yamaguchi, Asuka Zeber, Emily, Dinh, Phiphi For everyone else, term paper is due on that date.
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Homework 5: Exploratorium Due Thursday, November 29 th
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Extra Credit: San Jose Ballet See a performance of San Jose Ballet in San Jose Center for Performing Arts (Nov. 15 th – 18 th ). Turn in your ticket receipt. Worth one homework assignment or three quiz/participation credits. Ramon Moreno in CARMINA BURANA
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Extra Credit: San Jose Museum of Art Visit the San Jose Museum of Art. Turn in your ticket receipt. Worth two quiz/participation credits. Richard Diebenkorn, Untitled (Albuquerque), 1952 Joan Miró, Untitled from Paroles Peintes, 1967.
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Final Exam Thursday, December 18th, 1215-1430 Exam will have eight short essay questions (4-8 sentences). Final exam will be based on the reading assignments and lecture topics since the midterm (see calendar). The exam counts as two homework assignments (out of a total of nine). May skip up to two homework assignments; if you don’t, I’ll drop the lowest scores.
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Course Grade The grade in the class is based on: First Term Paper Second Term Paper Oral Presentation In-class Participation (Quizzes, Activities) Homework (Final counts as 2 homeworks) Each counts towards 20% of your grade
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Quiz The Shroud of Turin is probably not the burial cloth of Christ because a)The pigment, burnt sienna, did not exist at the time of Christ b)Carbon dating of the flax cloth marks it as being from the 14 th century. c)Computer reconstruction of the face reveals that the features are those of a woman. d)Trace fibers of a plastic, nylon brush have been found in the image e)None of the above.
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Seeing Color
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Spectrum of Visible Light
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Wavelengths & Photons Red Photon Blue Photon Green Photon Yellow Photon Prism Spectrum Particles of light, called photons, each have a wavelength.
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Newton’s Color Wheel Prism spectrum is a straight line, so why did Isaac Newton describe color using a circular wheel?
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Additive Color Wheel Spectral Colors There are No Photons of These Colors R Y B G M C Red Yellow Green Cyan Blue Magenta
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Adding Color Lights Stream of red & green photons looks same as yellow photons (metamerism) Theatrical lighting or YELLOW Eye to Brain white Notice overlap of red, green, & blue is seen as white light
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Trichromatic Theorists Thomas Young (1773-1829) English physicist Hermann von Helmholtz (1821-1894) German physicist James Clerk Maxwell (1831-1879) Scottish physicist
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Simple Trichromatic Theory Yellow & Red photons excite me Yellow, Green & Cyan photons excite me Cyan & Blue photons excite me Inside your eye there are three receptors MOE CURLY LARRY
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Trichromatic: Seeing Yellow Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. I’M EXCITED Cyan & Blue photons excite me. Yawn. Yellow seen when Curly and Larry excited, either by yellow photons or red & green photons. MOE CURLY LARRY OR
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Seeing Yellow Sodium lamps emit pure yellow photons Color monitor can only emit red, green, and blue (RGB); creates other colors by selectively turning RGB pixels on or off.
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Trichromatic: Seeing Magenta Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. Yawn. Cyan & Blue photons excite me. I’M EXCITED Magenta is seen by eye when Moe and Larry excited, which no single type of photon can achieve. MOE CURLY LARRY
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Maxwell Color Disk Disk painted half red, half blue looks magenta when rapidly spinning.
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White Trichromatic: Seeing White Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. I’M EXCITED Cyan & Blue photons excite me. I’M EXCITED White seen when all three very excited Gray seen when all three less excited MOE CURLY LARRY
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Trichromatic: Color Blindness Red, Yellow, Green & Cyan photons excite me. I’M EXCITED Cyan & Blue photons excite me. Yawn. MOE CURLY LARRY Color blindness occurs if the eye is missing one of the three receptors. Other receptors try to compensate but cannot distinguish some colors. Do I see red or green? OR
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Color Blindness Classification Incidence (%) MalesFemales Anomalous Trichromacy 6.30.37 Protanomaly (Red-cone weak) 1.30.02 Deuteranomaly (Green-cone weak) 5.00.35 Tritanomaly (Blue-cone weak) 0.0001 Dichromacy2.40.03 Protanopia (Red-cone absent) 1.30.02 Deuteranopia (Green-cone absent) 1.20.01 Tritanopia (Blue-cone absent) 0.0010.03 Rod Monochromacy (no cones) 0.00001 29 or 70? 21 or 74? Weakness or absence of one of the three types of cones is the cause of color blindness, leading to a reduced ability to distinguish colors.
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Trichromatic: After-Image First stare at RED I’M EXCITED! Yawn. MOE CURLY LARRY Me too, but tired. ME TOO! I’M EXCITED ! MOE CURLY LARRY Then stare at WHITE Moe and Curly are excited so what color is seen? CYAN (light blue-green)
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Negative After-image Stare, unfocused, at the red cross for 10 seconds then look at white wall
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Negative After-image Cyan
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Negative After-image Stare, unfocused, at the flag for 10 seconds then look at white wall
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Negative After-image Cyan Magenta Yellow
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Additive Complements LARRY MOE CURLY After-image of red is cyan because Larry gets tired so when white light excites all three Stooges, Moe & Curly stronger than Larry. R C Cyan Cyan = White - Red
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Trichromatic: Opponency Yellow & Red photons excite me. I’M EXCITED Yellow, Green & Cyan photons excite me. I’M EXCITED Oh, Shut The F*@% Up! Yellow seen when Curly and Larry excited, which can annoy Moe, who then opposes them. MOE CURLY LARRY Shine Red & Green photons (or Yellow photons)
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Simultaneous Contrast Are the two gray bars the same shade of gray? Yes, the presence of a nearby color affects perception of both hue and value, shifting both towards complement Does the gray bar look slightly bluish?
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Color Vision in the Eye Three types of cones (color) One type of rod (B/W only)
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Additive Color Wheel R Y B G M C Additive Primary Colors Red Green Blue Secondary Colors Yellow (Red+Green) Cyan (Green+Blue) Magenta (Blue+Red) Human eye has three types of cone cells, sensitive to red, green, and blue
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Why Yellow & Orange are Special Blue Red Green Cone Sensitivity Peak sensitivities of green and red cone are close together, so we easily separate colors in this range, probably to spot ripe fruit and … Wavelength La Victoria Hot Sauce Compare the differences going from green to red… to going from green to blue.
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Hue, Saturation, Value Color wheel is not a single wheel but stack of wheels that range in value. HUE VALUE SATURATION
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Saturation & Distance Look carefully at the color of the grassy field in the foreground, mid-ground, and background. The field in the background is less saturated (grayish) and also somewhat bluer.
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Atmospheric Perspective Objects in the distance have a bluish, unsaturated color due to atmospheric scattering of blue light (same as blue sky). Artists use this effect to suggest distance.
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CIE Hue-Saturation Diagram Eye is not a perfect optical instrument. Color “wheel” is actually distorted cone shape. Rim is full saturation, center is white LARRY % CURLY % 50% Larry 50% Curly 0% Moe 33% Larry 33% Curly 33% Moe
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Next Lecture Visual Arts @ Nexus Remember: Assignment due: Homework #5 (Visit Exploratorium)
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