Upcoming Deadlines
Homework #13 – Creating Stereoscopic 3D ImagesDue Tuesday, May 15th (Last day of classes)20 points (10 points if late)
Final Exam - Tuesday, May 22nd from 1215 to 1430 in this room.
All assignments and extra credit due on May 22nd
For full schedule, visit course website:ArtPhysics123.pbworks.com
Pick up a clicker, find the right channel, and enter Student ID
Homework #13
Creating stereoscopic 3D images.
For this assignment you will create at least three different stereoscopic images from photographs.
At least one of the images should have you appearing in the photo and at least one of the images should be a recognizable location on campus.
You will be graded on the composition so plan your scenes to make them interesting (especially for 3D).
Stereo 3D Photos with Photoshop
Steps for creating stereo 3D photos in Photoshop:
1)Snap a photo, move 3 inches to the right, take a second photo. Avoid having objects closer than a yard away from the camera and no moving objects!2)Open both images in Photoshop. Hold the shift key and drag the right eye image on to left eye image.3)Rename the layers “Right Eye” and “Left Eye”; make sure the Right Eye layer is on top.4)Double click the Right Eye thumbnail to open the Blending Window. In Advanced Blending uncheck the Red Channel for Red/Cyan glasses (or Green Channel for Green/Magenta glasses).
Stereo 3D Photos with PhotoShop
Uncheck the Red Channel
Select Right Eye Layer
Homework #13
Course website has details and tips on making 3D photos.
Upload your photos to your blog in an entry entitled “Creating Stereoscopic 3D Images”
Extra Credit: You can also create a pair of stereo-ready images in Autodesk Maya by rendering a scene for one image, then shifting the camera position and rendering the second image.
Extra Credit: Create a 3D animated short, either by stop motion or in Maya. Ten bonus points for a good animation; twenty bonus points for a great one.
Student Evaluation
Need a volunteer to distribute and collect student evaluations.
Volunteer should deposit the packet of completed forms in the mailbox at front door of the building (exit to Tower Hall).
Evaluations
When finished, find me in Room 242
Survey Question
This course has four parts; which part was the least interesting for you:
A) Basic Animation (Falling, etc.)
B) Character Animation (Walks, etc.)
C) Effect Animation (Waves, etc.)
D) Lighting (Shadows, Color, etc.)
E) About the same for all four
Review Question
Red Cone
Green Cone
Blue Cone
What color do you see when your eye receives both red and blue photons?
A) YellowB) GreenC) MagentaD) CyanE) White
Review Question
C) Magenta
This is nicely demonstrated with the spinning Maxwell disk.
Review Question
The ear hears sound waves and senses the wavelength of the sound as the pitch.
The eye sees light waves and senses the wavelength of the light as color.
The ear doesn’t have a “lens” so it can’t form an image but otherwise the ear and the eye are very similar. True or False
The Ear vs. The Eye
AE D
How the ear senses sound waves is distinct from how the eye senses light waves.
Hearing an E and a D together does not sound like an A.
Seeing green and red together does look like yellow light.
Review QuestionIf you stare at a red cross for a few seconds and then look at a white wall, the after-image you see is cyan. What color is the after-image if the cross is blue?
A)RedB)YellowC)GreenD)MagentaE)Orange
Red cross
After-image
Blue cross
Negative After-image
Stare, unfocused, at the red cross for 10 seconds then look at white wall
Negative After-image
Yellow
Additive Complements
After-image of blue cross is yellow since blue cone gets tired so when white light excites all three cones, red & green cone signals are stronger than blue cone.
Yellow = White - Blue
R
GB
Making Color
Spectrum & Color
Wavelength
Brig
htne
ss
The color you see depends on the spectrum of the light waves reaching your eye.
X Y Z
Tristimulus Values
There’s a complicated mathematical formula to get the tristimulus values from the spectrum curve.
WavelengthB
righ
tne
ss
X = 0.2Y = 0.7Z = 0.1
Creating Colored Light
Two basic ways of creating colored light:
Light source produces colored light.
Absorb some of the light’s wavelengths.
Filter
Thermal Light Sources
When objects glow with heat they emit light in a broad spectrum, called the blackbody spectrum.
The peak of that spectrum shifts from red to blue as the temperature increases.
Thermal Light Sources
Notice that the color of thermal light sources goes from red (2000K) to blue (12000K) but it is never green.
Spectrum is broad around 6000K so we see it as white.
CIE “Color Wheel”
Solar Spectrum
UV Visible Infrared
Brig
htne
ss
Spectrum of the Sun is brightest in the range of wavelengths that are visible to us (adapted by evolution).
Sun is so bright at all visible wavelengths that it’s seen as white or unsaturated yellow.
Spectral Lines
Some light sources produce spectra with lines, indicating wavelengths for which the atoms have resonant oscillations.
Neon lamp
% Red Cone
% G
ree
n C
on
e
Neon lamps produce a well-saturated red, but not as pure as sodium lamp’s yellow
Spectral Reflectance Curves
When white light shines on a colored object, some photons are absorbed, others are reflected by the object’s surface.
RedW
hite
Printing InksPrinting inks use only three bright pigments:
• Yellow• Magenta• Cyan
Yellow
Cyan
Magenta
Red
Green
Blue(also use black ink, which is cheaper than mixing for black)
Mixing Yellow & Cyan Inks
Bright Yellow
BrightCyan
BLUE GREEN RE
&
Green
Subtractive ColorFind mixture color by simple color “arithmetic.”
Yellow = Red+GreenCyan = Blue+GreenMagenta = Blue+Red
So mixing:Yellow & Cyan = Green
Yellow
Red
R
Y
B G
M
C
Yellow
Cyan
Magenta
Red
Green
Blue
Four Color PrintingMagenta Yellow Cyan Black
Magenta+ Yellow+ Cyan
All Four
Green balloon printed with mix of yellow and cyan inks
Paint Pigments
Paints are suspensions of pigment particles.
Different types of paint (watercolor, acrylic, oil, gouache, etc.) are just different binding solutions for holding pigment.
Name That Pigment
Titanium White
Cadmium Red
Burnt Sienna
BLUE GREEN RED
0%
100%BLUE GREEN RED BLUE GREEN RED
Re
flect
an
ce P
erce
nta
ge
Name That Pigment
Phthalocyanine Green
Cadmium Yellow
Cobalt Blue
BLUE GREEN RED
0%
100%BLUE GREEN RED BLUE GREEN RED
Re
flect
an
ce P
erce
nta
ge
Artist’s Handbook
These spectral reflectance curves and those of many other standard pigments are found in Mayer’s book.
Color Subtraction
% Red Cone
% G
ree
n C
on
e
Combining pigments is more complicated and the resulting
color is difficult to predict.Learn by practice Green
paint
Red paint
Dark Brown
Mixing Yellow & Blue Paint
% Red Cone
% G
ree
n C
on
e
Mixtures of yellow and blue paint often mix to green
Bluepaint
Yellowpaint
Green
By contrast, adding yellow and blue lights
gives white light
Mixing Yellow & Blue
Bright Yellow
Blue
&
Bluish Green
Yellow absorbs much of the Blue
Blue absorbs much of the Red
Ref
lect
ance
%
Mixing Red & Blue
Blue
&
Crap
Red
Reflectance curves for pigments and their mixture
Effect of the Light Source
The color of an object depends on both the spectral reflectance curve and on the spectrum of the light shining on the object.
White
RedGreen ?
Magenta ?
Same “red” object in different lights
Pigment Value & Light Source
Yellow pigment under blue light is dark gray.
Cadmium Yellow
BLUE GREEN RED
Put paint swatch in this area
Pigment Value & Light Source
Yellow pigment under red light is bright red
Cadmium Yellow
BLUE GREEN RED
Put paint swatch in this area
Demo: AlexandriteThe color change from red to green is due to strong absorption of light in a narrow yellow portion of the spectrum, while allowing large bands of blue-greener and red wavelengths to be transmitted. Typically, alexandrite has an emerald-green color in daylight (relatively blue illumination of high color temperature) but exhibits a raspberry-red color in incandescent light (relatively yellow illumination).
Sunlight or FlorescentIncandescent light
Demo: Sodium Lamp
Sodium lamps produce a true, spectral yellow light
Pile of toy balloons
Demo: Sodium Lamp
Sodium light
Florescent light
Light Source, Value, Saturation
The value and saturation of an object’s color also depend on the spectrum and the intensity of the light shining on the object.
DimRed
Same “red” object in different lights
Bright Pink
Saturation & Value
High Value andLow Saturation
Low Value andHigh Saturation
As lighting conditions change, value and saturation usually vary together.
Valu
e
Saturation
Valu
e
Saturation
Black, White, Gray
% Red Cone
% G
ree
n C
on
e
33 %
33%
33%
Black, white, and gray are all the same hue, just different
values (brightness)
Experiment
Photographed black felt and white flannel tablecloths
Black or White?
Black or White?
Black or White?
Black Paint
Black paint reflects more light (has higher value) than you may think.
Compare the value of the matte black paint with that of the holes.
True Black
The closest you can get to true black is a hole that lets light in but not back out.
Surprisingly, even the lunch box painted white inside doesn’t reflect much light out the hole.
White in the shadow is darker than black in the light.
Last LectureStereoscopic (3D) Films*Bring Your 3D Glasses*
Homework 13 (Creating 3D Images) due Tuesday, May 15th (Last day of Class)
Please turn off and return the clickers!