the physics of colour
TRANSCRIPT
THE PHYSICS OF COLOUR
Mi losz Michalski
Institute of PhysicsNicolaus Copernicus University
July 3, 2012
Mi losz Michalski THE PHYSICS OF COLOUR
Overview
Waves and wave phenomena
The spectrum of electromagnetic radiation
The physiology of colour perception — eye and brain
Colour of light, colour of an object, colour models and spaces
Mi losz Michalski THE PHYSICS OF COLOUR
Overview
Waves and wave phenomena
The spectrum of electromagnetic radiation
The physiology of colour perception — eye and brain
Colour of light, colour of an object, colour models and spaces
Mi losz Michalski THE PHYSICS OF COLOUR
Overview
Waves and wave phenomena
The spectrum of electromagnetic radiation
The physiology of colour perception — eye and brain
Colour of light, colour of an object, colour models and spaces
Mi losz Michalski THE PHYSICS OF COLOUR
Overview
Waves and wave phenomena
The spectrum of electromagnetic radiation
The physiology of colour perception — eye and brain
Colour of light, colour of an object, colour models and spaces
Mi losz Michalski THE PHYSICS OF COLOUR
Overview
Waves and wave phenomena
The spectrum of electromagnetic radiation
The physiology of colour perception — eye and brain
Colour of light, colour of an object, colour models and spaces
Mi losz Michalski THE PHYSICS OF COLOUR
Waves
Mi losz Michalski THE PHYSICS OF COLOUR
Waves
Transversal mechanical waves
Mi losz Michalski THE PHYSICS OF COLOUR
Waves
Longitudinal sound waves
air
Mi losz Michalski THE PHYSICS OF COLOUR
Waves
Electromagnetic waves
electric field magnetic field
Mi losz Michalski THE PHYSICS OF COLOUR
Waves — length, frequecy and phase
Length and frequency
l longlow frequency
shorthigh frequency
Mi losz Michalski THE PHYSICS OF COLOUR
Waves — length, frequecy and phase
Phase
in phase
Mi losz Michalski THE PHYSICS OF COLOUR
Waves — length, frequecy and phase
Phase
out of phase
D
Mi losz Michalski THE PHYSICS OF COLOUR
Energy carried by the electromagnetic wave
E = hν
high frequency = high energy
low frequency = low energy
Mi losz Michalski THE PHYSICS OF COLOUR
The electromagnetic spectrum
Increasing frequency
Increasing wavelengthvisible spectrum
wavelenght in nm
0.0004 - 0.0007 mm
Mi losz Michalski THE PHYSICS OF COLOUR
The electromagnetic spectrum
Mi losz Michalski THE PHYSICS OF COLOUR
Wave phenomena
Reflection
Diffraction, interference, disperssion, polarization...
Refraction
Mi losz Michalski THE PHYSICS OF COLOUR
Wave phenomena
Reflection
Diffraction, interference, disperssion, polarization...
Refraction
Mi losz Michalski THE PHYSICS OF COLOUR
Wave phenomena
Reflection
Diffraction, interference, disperssion, polarization...
Refraction
Mi losz Michalski THE PHYSICS OF COLOUR
Wave phenomena
Reflection
Diffraction, interference, disperssion, polarization...
Refraction
Mi losz Michalski THE PHYSICS OF COLOUR
Wave phenomena
Reflection
Diffraction, interference, disperssion, polarization...
Refraction
Mi losz Michalski THE PHYSICS OF COLOUR
Wave phenomena
Reflection
Diffraction, interference, disperssion, polarization...
Refraction
Mi losz Michalski THE PHYSICS OF COLOUR
Refraction
aa
b
dependence on material properties — refraction index
nwater = 1.33, nglass = 1.52, ndiamond = 2.24
dependence on frequency
n ∼ ν
Mi losz Michalski THE PHYSICS OF COLOUR
Refraction
aa
b
dependence on material properties — refraction index
nwater = 1.33, nglass = 1.52, ndiamond = 2.24
dependence on frequency
n ∼ ν
Mi losz Michalski THE PHYSICS OF COLOUR
Refraction
aa
b
dependence on material properties — refraction index
nwater = 1.33, nglass = 1.52, ndiamond = 2.24
dependence on frequency
n ∼ ν
Mi losz Michalski THE PHYSICS OF COLOUR
Spectroscopy — characteristics of light sources
Mi losz Michalski THE PHYSICS OF COLOUR
Spectroscopy — characteristics of light sources
Mi losz Michalski THE PHYSICS OF COLOUR
Colour perception
Mi losz Michalski THE PHYSICS OF COLOUR
Three-component theory (trichromacy)
Rods and Cones
Mi losz Michalski THE PHYSICS OF COLOUR
Three-component theory (trichromacy)
Rode response to incident wavelength
Mi losz Michalski THE PHYSICS OF COLOUR
Three-component theory (trichromacy)
Cone response curves
Mi losz Michalski THE PHYSICS OF COLOUR
Three-component theory (trichromacy)
Cone response curves - idealized
S M L
Mi losz Michalski THE PHYSICS OF COLOUR
Three-component theory (trichromacy)
Mi losz Michalski THE PHYSICS OF COLOUR
Anatomical facts
Cones constitute about 5% of retina cells
Primates are trichromats, but many mammals are dichromats,nocturnal animals — no colour vision at all
Other animals (birds, fish) can be tetra- or pentachromats
The record holder is the Mantis shrimp — 12 cone types!
50% of women are genetically tetrachromats
Mi losz Michalski THE PHYSICS OF COLOUR
Anatomical facts
Cones constitute about 5% of retina cells
Primates are trichromats, but many mammals are dichromats,nocturnal animals — no colour vision at all
Other animals (birds, fish) can be tetra- or pentachromats
The record holder is the Mantis shrimp — 12 cone types!
50% of women are genetically tetrachromats
Mi losz Michalski THE PHYSICS OF COLOUR
Anatomical facts
Cones constitute about 5% of retina cells
Primates are trichromats, but many mammals are dichromats,nocturnal animals — no colour vision at all
Other animals (birds, fish) can be tetra- or pentachromats
The record holder is the Mantis shrimp — 12 cone types!
50% of women are genetically tetrachromats
Mi losz Michalski THE PHYSICS OF COLOUR
Anatomical facts
Cones constitute about 5% of retina cells
Primates are trichromats, but many mammals are dichromats,nocturnal animals — no colour vision at all
Other animals (birds, fish) can be tetra- or pentachromats
The record holder is the Mantis shrimp — 12 cone types!
50% of women are genetically tetrachromats
Mi losz Michalski THE PHYSICS OF COLOUR
Anatomical facts
Cones constitute about 5% of retina cells
Primates are trichromats, but many mammals are dichromats,nocturnal animals — no colour vision at all
Other animals (birds, fish) can be tetra- or pentachromats
The record holder is the Mantis shrimp — 12 cone types!
50% of women are genetically tetrachromats
Mi losz Michalski THE PHYSICS OF COLOUR
Anatomical facts
Cones constitute about 5% of retina cells
Primates are trichromats, but many mammals are dichromats,nocturnal animals — no colour vision at all
Other animals (birds, fish) can be tetra- or pentachromats
The record holder is the Mantis shrimp — 12 cone types!
50% of women are genetically tetrachromats
Mi losz Michalski THE PHYSICS OF COLOUR
XYZ colour representation
X
X
Y
Y
Z
Z
Mi losz Michalski THE PHYSICS OF COLOUR
XYZ colour representation
X Y Z
Mi losz Michalski THE PHYSICS OF COLOUR
Psychology of colour perception
Opponent color theory
Some pairs of basic colours blend together well...
+ +
... while some do not:
+ + +
The brain takes account of differences of some cone outputs
Mi losz Michalski THE PHYSICS OF COLOUR
Psychology of colour perception
Opponent color theory
Some pairs of basic colours blend together well...
+ +
... while some do not:
+ + +
The brain takes account of differences of some cone outputs
Mi losz Michalski THE PHYSICS OF COLOUR
Psychology of colour perception
Opponent color theory
Some pairs of basic colours blend together well...
+ +
... while some do not:
+ + +
The brain takes account of differences of some cone outputs
Mi losz Michalski THE PHYSICS OF COLOUR
Psychology of colour perception
Opponent color theory
Some pairs of basic colours blend together well...
+ +
... while some do not:
+ + +
The brain takes account of differences of some cone outputs
Mi losz Michalski THE PHYSICS OF COLOUR
Preprocessing signals from cones
Mi losz Michalski THE PHYSICS OF COLOUR
Psychology of colour perception
R
G
B
C
M
Y
Afterimages result from the fatigue of cones of one type andtemporary weakening of their response
Mi losz Michalski THE PHYSICS OF COLOUR
Psychology of colour perception
R
G
B
C
M
Y
Afterimages result from the fatigue of cones of one type andtemporary weakening of their response
Mi losz Michalski THE PHYSICS OF COLOUR
Colour of objects
Pigments change the color of reflected lightas the result of selective wavelength absorption
Colour of an object depends on that of incidednt light
Mi losz Michalski THE PHYSICS OF COLOUR
Colour of objects
Pigments change the color of reflected lightas the result of selective wavelength absorption
Colour of an object depends on that of incidednt light
Mi losz Michalski THE PHYSICS OF COLOUR
Colour of objects
Pigments change the color of reflected lightas the result of selective wavelength absorption
Colour of an object depends on that of incidednt light
Mi losz Michalski THE PHYSICS OF COLOUR
Colour of objects
Pigments change the color of reflected lightas the result of selective wavelength absorption
Colour of an object depends on that of incidednt light
Mi losz Michalski THE PHYSICS OF COLOUR
Colour of objects
Pigments change the color of reflected lightas the result of selective wavelength absorption
Colour of an object depends on that of incidednt light
Mi losz Michalski THE PHYSICS OF COLOUR
Colour models and colour spaces
Colour models — mathematical, parametric systems of colourrepresentation: RGB, HSV, Lab, CMYK, ...
(226,189,15) = (7,20,94,0) = (49,93,89)
RGB CMYK HSB
Colour space — fixing model baseby specifying e.g. what is pure R,pure G, and pure B
Mi losz Michalski THE PHYSICS OF COLOUR
Colour models and colour spaces
Colour models — mathematical, parametric systems of colourrepresentation: RGB, HSV, Lab, CMYK, ...
(226,189,15) = (7,20,94,0) = (49,93,89)
RGB CMYK HSB
Colour space — fixing model baseby specifying e.g. what is pure R,pure G, and pure B
Mi losz Michalski THE PHYSICS OF COLOUR
Colour models and colour spaces
Colour models — mathematical, parametric systems of colourrepresentation: RGB, HSV, Lab, CMYK, ...
(226,189,15) = (7,20,94,0) = (49,93,89)
RGB CMYK HSB
Colour space — fixing model baseby specifying e.g. what is pure R,pure G, and pure B
Mi losz Michalski THE PHYSICS OF COLOUR
Colour models and colour spaces
Colour models — mathematical, parametric systems of colourrepresentation: RGB, HSV, Lab, CMYK, ...
(226,189,15) = (7,20,94,0) = (49,93,89)
RGB CMYK HSB
Colour space — fixing model baseby specifying e.g. what is pure R,pure G, and pure B
Mi losz Michalski THE PHYSICS OF COLOUR
RGB
0,0,0 0,0,255 255,0,255
0,255,255
128,128,128
255,0,0255,255,0
255,255,255
Mi losz Michalski THE PHYSICS OF COLOUR
RGB
0,0,0 0,0,255 255,0,255
0,255,255
128,128,128
255,0,0255,255,0
255,255,255
Mi losz Michalski THE PHYSICS OF COLOUR
CMYK
C
M
Y
K
Mi losz Michalski THE PHYSICS OF COLOUR
CMYK
Mi losz Michalski THE PHYSICS OF COLOUR
The physics of colour
Thank you for your attention!
Mi losz Michalski THE PHYSICS OF COLOUR
The physics of colour
Thank you for your attention!
Mi losz Michalski THE PHYSICS OF COLOUR