Here are the points one should know while designing anything using colours. Terms like Hue, Saturation, Brightness, RGB, CMYK, Color Wheel are well explained here. One can also know about palletes and colour models. Please also read my presentation on Image file formats to know almost all basics related to designing on computers.

1. A Programme Under the compumitra Series
Copyright 2010-2015 © Sunmitra Education Technologies Limited, India
"They'll sell you thousands of greens. Veronese green and
emerald green and cadmium green and any sort of green you
like; but that particular green, never."
Pablo Picasso, 1966.
COLORS

2. Outline
About Colours.
Colour Related
Terms.
Colour Groups.
Colour
Palettes/Models.

3. About Colours

4. What is COLOUR
Colour (or spelled as Color) is the property perceived by
our eyes that represents the wavelength of light. It is
sensed by cones and rods (types of cell) in our retina
and then interpreted by our brain.
A non-emissive objects colour means a particular colour
(wavelength) of light that it reflects while all other colours
it absorbs. A black body absorbs all colours in light while
a white body reflects every colour of light. For an
emmissive object obviously a combination colour based
on incident light and emitted light shall be visible.
.

5. Understanding Colour Perception
Aristotle related colour to light but It was Sir Isaac
Newton who experimentally established this
relationship.
Colours are perceived by three different type of cells in
our retina. One can roughly assume it to be equivalent
to perceptors of Red, Blue and Green Colours.
This matches the the concept of 'TRICHROMATIC
THEORY' given by Thomas Young in 1801. This was
further endorsed by James Clerk Maxwell.
The signal that is finally transmitted to our brain is
actually perceived as differential measurement between
RED-GREEN, BLUE-YELLOW and BLACK-WHITE.
This concept is explained by 'OPPONENT PROCESS
THEORY' given by Helmhotz and Ewald Hering.
Colour sensation in the brain is done by LGN (lateral
geniculate nucleus) in the Thalamus.
Human beings can distinguish about 10 million colours.

6. Some Interesting Facts About Colours
Almost half the women population have 4
types of colour receptors that make them
sense a large number of colours and
effectively a better colour sense. This is
possible due to presence of two X
chromosomes in woman.
4 receptors are available in many species
of spiders, marsupials (kangaroos), birds
and reptiles.
Afterimages made of complementary
colours are often seen after exposure to
strong light beams.

7. Colour Related Terms

8. Terms List
Hue
Saturation
Brightness/Lightness
Shade
Tint and Tone
Pigment and Dye

9. Hue
The colour element is called the
hue.
It is the degree to which a particular
colour is explained in terms of basic
colours such as RED, GREEN,
YELLOW, BLUE Etc.
For e.g. Yellowish Red, Greenish
Yellow etc.

10. Saturation
It is the perceived intensity of a
colour. For e,g. RED, BRIGHT RED,
INTENSE RED.
Practically the lightness also
appears to be increased when
saturation is increased.
Saturation 200%

11. BRIGHTNESS/LIGHTNESS
It is the perceived
brightness or a shift
towards whiteness of a
particular colour.

12. SHADE
A colour made darker by adding
black is called its shaded version.
For e.g. sunlight falling on an object
creates a shadow, which often
requires shaded colours.
Shades of Blue

13. Tint and Tone
Mixture of colour with white is called
creating various tints of a colour.
Mixture of colour with grey is called
creating various tints of a colour.

14. Understanding HSL once again.
In a color sphere ,Colors of the same hue and
saturation, but of different lightness, are said to
be tints and shades. Colors of the same hue and
lightness, but of varying saturation, are called tones

15. Pigment and Dye
Pigment is a material that is added
to a substance to change the colour
of its reflected light.
Dye is usually the soluble substance
to change the colour of a solution.

16. Colour Groups

17. List of Colour Groups
PRIMARY COLOURS
SECONDARY COLOURS
TERTIARY COLOURS
NEUTRAL COLOURS
COMPLEMENTARY and
SUPPLEMENTARY Colours
RAINBOW

18. PRIMARY COLOURS
It is a set of colours used in a
particular mix to form all other
colours.
For emmissive light or CRT the
primary colours are RED, GREEN
and BLUE. These are additive
primaries.
For print medium it is CYAN,
MAGENTA, YELLOW and BLACK.
These are subtractive primaries.
For Artists it is RED, YELLOW and
BLUE.

19. SECONDARY COLOURS
Colours formed by mixing primary colours are
called
secondary colours.
For RGB primaries it would be
Red + Green = Yellow,
Green + Blue = Cyan
Blue + Red = Magenta
For CMY Primaries it would be
Cyan + Magenta = Blue
Magenta + Yellow = Red
Yellow + Cyan = Green
For painters it is
Red + Yellow = Orange
Yellow + Blue = Green
Blue + Red = Violet

20. Tertiary Colours
Tertiary colours are mix of primary
and secondary colours. For e.g.
Red + Yellow = Orange.
Red + Magenta = Rose.

21. Neutral Colours
Shades ranging from Black to White
are called neutral colours. These are
popularly called grey shades.
These may have very light mix of
other colours. These are also called
low chroma shades.

22. Complementary and Supplementary colours
Colours treated as opposite in hue in the
same colour model. For e.g.
in RGB Model
Cyan is complementary of RED.
Yellow is Complementary of BLUE.
In traditional painting.
RED is complementary of GREEN.
Also nearby Tertiary colours on the wheel
are called Supplementary colours. For e.g.
ORANGE is Supplementary to RED.
Usually an aesthetic design is the best
combination of Complementary and
Supplementary Colours.

23. RAINBOW
Rainbow is a naturally occurring colour
group which is uniformly divided on the
basis of wavelength of light.
It is an excellent aesthetic combination
too.
The colour set is :
V – Violet
I – Indigo
B – Blue
G – Green
Y – Yellow
O – Orange
R - Red

24. COLOUR PALLETES/MODELS

25. LIST OF
PALLETES/MODELS
RGB
CMYK
HSB
UNIFORM
SVG
PANTONE
TRUMATCH

26. RGB (Red, Green, Blue)
This palette set is meant for
images to be displayed on screen
or CRTs.
Maximum number of shades
possible is dependent on system
features.
By default 100 preset default
shades are provided in Coreldraw
Application.
For 24 bit colour set 16.7 million
shades are possible.
Value for R, G and B can be
individually set from 0 to 255.

27. CMYK (Cyan, Magenta, Yellow, Black)
'K' in CMYK comes from Black
coloured Key in CMYK printing
system.
This model is meant for traditional
as well as digital printing system as
printing systems are based on
subtractive colours (all colours are
absorbed only required one is
reflected).
Values are set between 0 to 100.

28. HSB (Hue, Saturation,
Brightness)
This model allows direct
value based selection of
Hue, Saturation and
Brightness values.
Hue values can be set
from 0 to 360 and
saturation and brightness
values can be set from 0 to
100.

29. SVG
Colour Set Standardised for
Scalable Vector Graphics (SVG)
comes under this model.
This colour set is often used for
Internet based scalable graphics.
SVG colours are made of RGB
components values between 0 to
255.

30. Uniform Colors
This set is useful for
screen based drawings
where colours are
scattered on the base of
their hue values.
This set is sometime
useful for easy access of
colours from the palette.

31. PANTONE
This is a set of colours standardised
by 'PANTONE' company.
This set is treated is most standard
set in the colour industry. Even the
national flag, logos etc specify
colour codes from this set.
It provides matching of colours on
various surfaces such as solid
uncoated, solid coated, metallic,
matte, metallic etc.

32. TRUMATCH
This is large set of palletes for 4
colour printing that allows easy
selection of colours based on HSB
model.
There are 50 hue families shown in
the order of the spectrum, with 40
perfectly proportioned tints and
shades of each hue plus a selection
of 4-color greys -- over 2,000
colors in all. The smooth, precisely
proportioned steps take the
guesswork out of 4-color selection
and matching.

33. Bibliographical Links
www.wikipedia.org
http://www.colorcube.com/articles/theory/glossary.h
tm
http://www.colormatters.com/colortheory.html
http://www.worqx.com/color/

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