Illumination terms

Question 1

Contrast

Answer 1

The degree of juxtaposition between light and dark.

Question 2

Low Contrast

Answer 2

Not much difference between light and dark

Question 3

High Contrast

Answer 3

Much difference between light and dark

Question 4

Contrast - Intensity

Answer 4

Measure of how bright or dark the brightest or darkest lights and shadows are as they are juxtaposed against each other.

Question 5

High Key Lighting

Answer 5

Shadows are washed out with a lot of light

Question 6

Low Key Lighting

Answer 6

Shadows are emphasized

Question 7

Film Latitude

Answer 7

A measure of a camera film to capture detail in both light and dark areas

Question 8

Glare

Answer 8

The phenomenon where light is so intense it appears to eat away at the borders of its source into the surrounding image.

Question 9

Highlight

Answer 9

An area which is illuminated better than its surroundings

Question 10

Hot Spot

Answer 10

A direct or indirect light source which is significantly more intense than its surroundings (possibly causing glare).

Question 11

Evenness

Answer 11

The quality of light in an image is not excessively contrasty.

Question 12

Volume Rendering

Answer 12

The ability for illumination to make forms and voids read more three dimensionally

Question 13

Coherence

Answer 13

When illumination makes spaces and forms easy to read

Question 14

Disorder

Answer 14

When illumination makes spaces and forms confusing and illegible

Question 15

Sparkle

Answer 15

A lighting effect usually caused by an abundance of point light sources which will create a shimmering effect on reflective surfaces

Question 16

Indirect

Answer 16

Illumination which is reflected or otherwise placed at a severe angle before shining onto the surfaces in view

Question 17

Curves

Answer 17

Curved surfaces are an interesting problem to solve for illumination, as light will appear to wrap around them and grade over their surfaces.

Question 18

Luminaires

Answer 18

Lighting fixtures

Question 19

Candle, Candle Power, or Candela (cd)

Answer 19

A unit of luminous intensity based on the light produced by one physical candle.

Question 20

Luminous Intensity

Answer 20

(a measure of the light emanating from a surface) The amount of light leaving a surface

Question 21

Luminous Flux / Flow

Answer 21

(the rate of flow of light) 1 Lumen passes through a 1 Square Foot opening in a 1 Foot radius sphere that has a 1 Candela source at the center.

Question 22

Illuminance

Answer 22

(a measure of light reaching a surface) 1 Foot Candle falls on a 1 Square Foot spherical surface 1 Foot away from a 1 Candela source

Question 23

Luminance

Answer 23

(a measure of light reflecting off of a surface) If a surface absorbs no light (it reflects all light) then its Luminance is 1 Foot Lambert

Question 24

Angle Of Incidence

Answer 24

Angle at which light hits a surface, small angle means light hits more directly, large angle means light hits more askew

Question 25

Specular Reflection

Answer 25

Light bounces off of a surface, angle of incidence equaling the angle of escape

Question 26

Transmission

Answer 26

Light passes through a surface.

Question 27

Diffuse

Answer 27

Light passing through or bouncing off of a surface spreads out and becomes unfocused

Question 28

Absorption

Answer 28

Light is turned into heat by the surface it hits

Question 29

Clear lens

Answer 29

Allows light through without altering its angle (though the angle changes slightly while inside of the lens, it escapes at the same angle it entered)

Question 30

Diffusing lens

Answer 30

Scatters light and obscures view of lamps

Question 31

Prismatic lens

Answer 31

Scatters vertical beams of light more than angled ones

Question 32

Reflectance p (rho)

Answer 32

ratio of exiting light to incident light

Question 33

Transmittance T

Answer 33

a measure of light passing through a surface

Question 34

Posterization

Answer 34

Makes blurred borders and graded washes into hard lines and sharp contrasts