Module 1 - Vision, Colour, Design Guide Flashcards
What is light?
Visually perceived radiant energy.
What are two theories about how light works?
Particle Theory
Wave Theory
What is visible light?
Small portion of electromagnetic spectrum from 380nm to 780nm.
What is a wavelength?
The size of periodically occurring wave, measured as the distance between any two corresponding points on successive waves.
What is frequency?
How often one part of a light wave occurs per second.
What is luminous flux?
The total amount (quantity) of light produced by a light source.
What is Φ the symbol for?
Luminous flux.
What is the unit of measure for luminous flux?
Lumen.
What is luminous intensity?
The strength of light in a specific direction.
What is the unit of measurement for luminous intensity?
Candela (cd)
What is the traditional term for the candela?
Candlepower (cp)
What is Illuminance?
The amount of light striking a surface.
What is the unit of measurement for Illuminance?
Lux or Footcandle
What is reflectance?
A measure of the ability of a surface to reflect light that arrives upon that surface.
What is luminous exitance?
Non-directional light reflected from or transmitted through a surface.
What is luminance?
Light directionally reflected from or transmitted through a surface.
What units are luminance expressed in?
Candela/sq. ft.
Candela/sq. meter
What are the four components of vision?
Source
Modifier
Eye
Brain
What are the optical components of the eye?
Cornea Aqueous humor Lens Iris Vitreous humor
What is the cornea?
A transparent membrane, the most forward surface of the eye.
What is the aqueous humor of the eye?
A clear, water-like substance that lies between the cornea and the lens.
What is the iris? (eye)
A coloured ring that that surrounds the pupil. It contains the muscles that cause the pupil to dilate and constrict to increase or decrease the amount of light entering the eye.
What does the lens of the eye do?
Changes shape to adjust the amount of optical power needed. Allows us to focus objects that lie at different distances in space onto the retina at the back of the eye.
What is the vitreous humor of the eye?
A jelly-like substance. Helps the eye to keep its shape.
What is the retina and what does it do?
The innermost layer of the eye that contains receptor cells, nerve cells, and blood vessels. The cells of the retina convert electromagnetic energy to chemical signals and, finally, to electrical impulses that nerve cells in the retina begin to process and deliver to the brain.
What are the two classes of visual receptor cells in the retina?
Rods and Cones
Cones are responsible for what type of vision?
High-level daytime photopic vision. Active in high light levels. Responsible for colour vision.
How many types of cones are there?
3
What light levels do rods operate under?
Low light levels.
What type of vision are rods responsible for?
Scotopic vision.
What is scotopic vision?
Low-level nighttime vision.
What type of information do rods provide?
The amount of light leaving a surface?
What is mesopic vision?
Neither photopic nor scotopic. How we see under many typical nighttime conditions.
What type of vision or cones responsible for?
Photopic vision/daytime vision.
What are cones color sensitivity?
Full color vision.