2. Color

Question 1

What are the three essential traits to color?

Answer 1

Value, hue, chroma

Question 2

What are seven traits that affect the esthetic appearance of teeth?

Answer 2

Value, hue, chroma, reflectiveness, translucency, contour, fluorescence?

Question 3

What are the three stages to color?

Answer 3

1. Light source
2. Object (optical properties of the object)
3. Vision/perception

Question 4

What are the two types of photoreceptors in human eyes?

Answer 4

1. Rods (extra sensitive, no color, darkness)

2. Cones (require brighter light, color)

Question 5

1-3. What are the three types of cones?

4. How are we able to see more than just these three colors?

Answer 5

1. Red
2. Blue
3. Green
4. Due to multiple levels (frequency and total number) of stimulation of these three cones

Question 6

Primary additive colors? The three combined produce what color?

Answer 6

Red, blue, green

Together: white

Question 7

Primary subtractive colors? The three combined produce what color?

Answer 7

Cyan, yellow, magenta

Together: black

Question 8

TV’s use additive or subtractive? How about printers?

How can both systems produce a variety of colors?

Answer 8

1. TV’s: Additive
2. Printers: Subtractive
3. Both systems stimulate the same 3 cones (red, blue, green)

Question 9

What are five general principles about vision/perception?

Answer 9

1. It is relative
2. Don’t stare too long
3. Adjustments to one, affects perceptions of others
4. Look at the gestalt (whole picture)
5. Your “focus” changes what you see

Question 10

Define metamerism

Answer 10

Two different materials that match under one light source but not another

Question 11

Define color temperature

Answer 11

The color of a light source and how that correlates to the color and temperature of an ideal black-body radiator

Question 12

What color temperature is used in dentistry?

Answer 12

5,500 Kelvin

Question 13

What is the Color Rendering Index (CRI)?

Answer 13

How good your light source is to an “ideal” light source, allowing for a more accurate depiction of color

Question 14

What is the range for the Color Rendering Index?

Answer 14

0 to 100 (with 100 being ideal)

Question 15

General principles on value/hue/chroma

• Which is the trickiest?
• Too significant of a value difference will make the lower value look ___
• ___ is meant for basic colors within the visible spectrum
• __ and ___ should be used together for polychromatic objects

Answer 15

1. Value
2. Grey
3. Hue
4. Hue and chroma

Question 16

Define refractive index

Answer 16

The factor by which light changes its speed, direction(s), and possibly wavelength as it goes through different mediums

Question 17

Define fluorescence

Matching fluorescence of a tooth is theorized to make it more like that you will match the ___

Answer 17

Light absorbed at a higher energy wavelength and emitted to a lower energy wavelength

Value

Question 18

CIE L*a*b* Color space
L - refers to?
A - refers to?
B - refers to?
Delta E means?

Answer 18

L - value
A - red-green
B - blue-yellow

Delta e means: distance calculated from the distances of all three axis

Question 19

CIE Lab* Color space

• Dimensional or dimensionless?
• Range?
• A delta E of 2 on average is or is not noticeable?

Answer 19

1. Dimensionless
2. 0-100
3. Not noticeable