slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
A Concise History of the Chromaticity Diagram from Newton to the CIE Standard Colorimetric Observer PowerPoint Presentation
Download Presentation
A Concise History of the Chromaticity Diagram from Newton to the CIE Standard Colorimetric Observer

Loading in 2 Seconds...

play fullscreen
1 / 61

A Concise History of the Chromaticity Diagram from Newton to the CIE Standard Colorimetric Observer - PowerPoint PPT Presentation


  • 556 Views
  • Uploaded on

A Concise History of the Chromaticity Diagram from Newton to the CIE Standard Colorimetric Observer Claudio Oleari Dipartimento di Fisica Università di Parma claudio.oleari@fis.unipr.it CREATE 2010, Gjøvik. I am not an historian (but I like History). !. !. warning

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'A Concise History of the Chromaticity Diagram from Newton to the CIE Standard Colorimetric Observer' - Renfred


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

A Concise History of the Chromaticity Diagramfrom Newton to the CIE Standard Colorimetric Observer

Claudio OleariDipartimento di FisicaUniversità di Parmaclaudio.oleari@fis.unipr.it

CREATE 2010, Gjøvik

slide2

I am not an historian

(but I like History)

!

slide3

!

warning

All phenomena that follow hold true for colour matching in aperture mode.

slide4

The historical steps

centre of gravity rule

three kind of photoreceptors (fibres)

tristimulus: colour measure inZERO ORDERapproximation

The standards CIE 1931-CIE 1964-CIE 1976OSA-UCS system (1947-1974)“Colour Appearance”: towards the colour measure inFIRST ORDERapproximation

The protagonists

1623 - Galilei

1704 - Newton

1802 - Young

1808 - (Göthe)

1852 - Helmholtz

1853 - Grassman

1857 - Maxwell

1872 - Hering

1920 - Schrödinger1931 ...

trichromacy

(Göthe against Newton)

Helmholtz-Hering Controversy

Le Blom, Palmer

slide6

Any colour computation needs colour measurement. But Colouris a sensation.

Then the question:Can colour be measured?

slide7

COLOUR IS SUBJECTIVE.

This could induce us to deny a priori the colour measurement.

On the contrary, colour can be measured because generally different persons agree in the judgment of the metameric colour matching, i.e. they affirm that different physical radiations appear equal.

(The comparison of the colour sensations among different individual observers is not required and the measurement of colour sensations is transformed into the physical measurement of the luminous radiations, which induce equal colour sensations in the normal observers.)

 A correspondence between luminous radiations and colour sensations is realised, consequently the colour is indirectly measured by measuring the luminous radiation.

slide9

Isaac Newton

New theory about light and colour (1671)Opticks (1704)

EXPERIMENTUM CRUCIS (1671)

No individual ray, no single refrangibility, is corresponding to white.

White in a heterogeneous mixture of differently refrangible rays.

Franco Giudice Ed., Isaac Newton, Scritti sula luce e sul colore, BUR, 2006

slide10

2 f

2 f

ADDITIVE SYNTHESIS OF SPECTRAL LIGHTS

slide11

CENTER OF GRAVITY RULE

Light Orange colour

slide14

2

Barycentric Coordinates and mixing colour lights

y

r

Y

R

balance scales

slide15

3

Barycentric Coordinates and mixing

independentcolour lights

(R,G,B)

r

b

g

r

g

b

Chromaticity Diagram

r = R/(R+G+B)

g = G/(R+G+B)

b = B/(R+G+B)

Barycentric Coordinates

B

G

R

slide16

Three lights are independent

if none of these lights is matched

by a mixture of the other two lights.

slide17

Barycentric Coordinates and mixing 4independent (?)colour lights

Can we use a three dimensional yoke in a four dimension space

NO! Because four independent colours are not existing!!TRICHROMACY

?

slide19

TRICHROMATIC COLOR RIPRODUCTION & REAL PRIMARIES

R

G

B

Instrumental reference frame

An RGB system cannot reproduce all the real colours!

slide20

Negative light source!?!?

- R

G

B

B + G - R = C ?????

B + G = R + C

C

Phenomenon explained by Maxwell 180 years later

slide21

B + G - R = C ?????

B + G = R + C = Q 

METAMERISM

+ R

G

C

B

Q

slide22

METAMERISM

… it is such an orange as may be made by mixing an homogeneal orange with a white in the proportion of the line OZ to the line ZY, ...

I. Newton

slide23

… it is such an orange as may be made by mixing an homogeneal orange with a white in the proportion of the line OZ to the line ZY, this proportion being NOTof the quantities of mixed orange and white powders, BUT the quantities of the lights reflected from them.

I. Newton

slide25

COLORI COMPLEMENTARI

COLORI COMPLEMENTARI ?!?!?

COMPLEMENTARY COLOURS ?!?!?

slide26

The existence of pairs of spectral lights that can be mixed to match white (complementary spectral lights) was not securely established until the middle of 1800.

White presented an especial difficulty for Newton, who wrote: (1671) - “There is no one sort of rays which alone can exhibit this [i.e. white]. This is ever compounded, and to its composition are requisite all the aforesaid primary colours.” (1704) - “if only two of the primary colours which in the circle are opposite to one another be mixed in an equal proportion , the point Z shall fall upon the centre O and yet the colour compounded of these two shall not be perfectly white, but some faint anonymous colour. For I could never yet by mixing only two primary colours produce a perfect white. Whether it may be compounded of a mixture of three taken at equal distance in the conference.”

Christian Huygens: (1673) – “two colours alone (yellow and blue) might be sufficient to yield white.”

slide27

Newton’s mistake and open problems:

  • angular position of the spectral lights (Primary Colours) on the colour circle are in relation to the musical notes and not to the colour complementarity
  • all the Magenta hues are represented by a point in the colour circle
  • Circular shape is only an approximation
slide32

Demichel (1924) – Neugebauer (1937)

Additive mixing of 8 colourlights

MAGENTA

YELLOW

CYAN

RED

BLUE

WHITE

GREEN

BLACK

slide33

Demichel (1924) – Neugebauer (1937)

Additive mixing of 8 colour lights

slide34

TRICHROMACY of colour mixture: impalpable trichromacy↔ ↔ material trichromacy

- TRICHROMACYand development of three-colour reproduction

- TRICHROMACY in opposition to Newton’s optics

slide35

Towards the definitionofimaginaryprimaries

1757 –MikhailVasil’evichLomonosov

1777 – George Palmer

1780 – John Elliot MD1802 – Thomas Young(1840 – David Brewster)

slide38

Thomas Young(1802)(1817)

  • Young’s contribution to understand Newton’s theory
  • Light is a wave phenomenon
  • Understanding of the light interference phenomenon
  • Trichromacy related to three kinds of “fibres” in the retina, differently resonating if crossed by light
  • Rotating disk for mixing colours (ClaudiusPtolomaeus ≈100 – 175)
slide39

Hermann von Helmholtz

(1852)(1855)(1866)

slide42

IMAGINARY PRIMARIES

Colour-Matching Functions in fundamental reference frame

slide45

Check of Newton’s centre of gravity rule

R

G

B

Dpt Exp.Psychology, Cambridge University

trilinear mixing triangle (c.1860)

slide46

Instrumental reference frameRed-Green-Blue real primaries

Fundamental reference frame imaginary primaries

Green

Red

Blue

slide49

Colour-Matching Functions:

Maxwell’s minimum saturation Method

R = 630.2 nm (rosso)

G = 525.1 nm (verde)

B = 456.9 nm (blu)

Colour matching of two beams

slide52

Ervin Schrödinger (1920)

- fundamental reference frame,- “Helligkeit” equation andAlychne- tristimulus space metrics

- Hering’s chromatic opponencies

slide53

tristimulus space and fundamental reference frame

Chromaticity diagram

König’s Colour-matching functions or König’s fundamentals

slide54

LUMINANCE

(R, G, B)

(eR, eG, eB)

Schrödinger’s “Helligkeit” equation

Lv=eRR+eGG+eBB

Exner’s

coefficients

slide56

l

=

l

y

(

)

V

(

)

l

x

(

)

Standard Colourimetric Observer CIE 1931

(D. B. Judd introduced the Schroedinger’s alychne)

Y

500

600

700

400

alychne

Z

X

slide58

CENTER OF GRAVITY RULE

q

q2

q1

q1

q2

q

W1

W2

Alychne

slide59

CENTER OF GRAVITY RULE

CIE 1931

Newton 1671 (1704)

slide61

Chromaticity diagram

tristimulus space and fundamental reference frame

König’s Colour-matching functions or König’s fundamentals