Light how

1
Light - how why we see
2
Electromagnetic Spectrum
3
(No Transcript)
4
The Eye
5
Camera Obscura
6

• Parable of
• the Blind Men and
• the Elephant

7
It was six men of Indostan To learning
much inclined, Who went to see the Elephant
(Though all of them were blind), That each by
observation Might satisfy his mind.
8
The First approached the Elephant, And
happening to fall Against his broad and sturdy
side, At once began to bawl God bless me!
but the Elephant Is very like a wall!
9
The Second, feeling of the tusk Cried, Ho!
what have we here So very round and smooth and
sharp? To me tis very clear This wonder of an
Elephant Is very like a spear!
10
The Third approached the animal And, happening
to take The squirming trunk within his hands
Thus boldly up he spake I see, quoth he, the
Elephant Is very like a snake!
11
The Fourth reached out an eager hand. And
felt about the knee What most this wondrous
beast is like Is very plain, quoth he Tis
clear enough the Elephant Is very like a
tree!
12

• The Fifth, who chanced to touch the ear,
• Said Een the blindest man
• Can tell what this resembles most
• Deny the fact who can
• This marvel of an Elephant
• Is very like a fan!

13

• The Sixth no sooner had begun
• About the beast to grope
• Than, seizing on the swinging tail
• That fell within his scope.
• I see, quoth he, the Elephant
• Is very like a rope!

14

• And so these men of Indostan
• Disputed loud and long,
• Each in his own opinion
• Exceeding stiff and strong.
• Though each was partly in the right,
• They all were in the wrong!

15
A composite of the Elephant the blind men saw
from their one experience.
16
Four Attributes of Visuals

• Color
• Form
• Depth
• Movement

17
Color Space (models)
Color is measured in degrees Kelvin
RGB (additive color)
CMYK (subtractive color)
18
Dots
One Dimension
The smallest irreducibly minimum unit of visual
communication (aka pixel)
19
Lines
One Dimension
When dots cannot be distinguished from each other
they become a line. A line is a dot in motion.
20
Shape
Two Dimensions
Line describes shape. There are three basic
shapes.
21
Eight depth cues

• Space
• Size
• Color
• Lighting

• Textural gradients
• Interposition
• Time
• Perspective

22
(No Transcript)
23
Movement

• Real Movement (unmediated)
• Apparent Movement (e.g. persistence of vision)
• Graphic Movement (i.e. left to right, top to
  bottom)
• Implied Movement (tension through diagonals, etc.)

24
Dog Story

• An example of the difficulties encountered in
  verbal communication when precise, unambiguous
  language is not or cannot be used.

25
I have a pet at home.
26
I have a pet at home.
Oh, what kind of pet?
27
It is a dog.
28
What kind of a dog?
It is a dog.
29
It is a St. Bernard.
30
Grown up or a puppy?
It is a St. Bernard.
31
It is full grown.
32
What color is it?
It is full grown.
33
It is brown and white.
34
Why didnt you say you had a full-grown,
brown and white St. Bernard as a pet in the
first place?
It is brown and white.
35
Why doesnt anybody understand me?
36
(No Transcript)