Colour Theory

College of Architecture, Trivandrum. ACHROMATIC COLOURS Black, white and gray, the colours devoid of hue

Black, white & gray are excluded from the Colours

CHROMA Chroma is the degree of saturation of a surface Colour GRAY An Achromatic colour, intermediate in lightness between black and white HUE The attribute of a Colour by which it is distinguished from another. All Colours are

judged to be similar to one or a proportion of two of the spectural hues together with

lightness and saturation hue is one of the three basic Colour terms. Physically hue is

determined by wavelength. SHADE Black added to a colour darkens the hue and makes shade of it. TINT White added to a colour makes its tint. TONE A colour differing slightly in any way from a specified colour. LIGHTNESS The amount of grey in a Colour. Lightness is also the attribute of a visual sensation,

by which an area is judged to transmit or reflect, diffusely a greater or smaller proportion of

the light falling on it.

Ex: brightness of a blue sweater may, decrease greatly when its wearer walks from

sun shine. Into shadow.

Legibility at a distance- legibility is the capability with which a figure or shape can be

recognized against its back ground.

--1--

BLACK ON YELLOW IS THE MOST LEGIBLE COMBINATION Black on orange

Yellow orange on navy blue

Black on white

Navy blue on white

White on navy blue.

SOLAR SPECTRUM Newton the profound thinker and discoverer of the laws of gravitation contributed

much to the science of light and color. He obtained a glass prism and, in a darkened room,

allowed a ray of sunlight to enter through a slit in a window shade and pass through the prism

the ray of light bend or refracted by passing through the prism, produced the beautiful band

of rainbow Colours that is called the solar spectrum.

Red, orange, yellow green, blue and violet, indigo. ILLUSION AND VISUAL EFFECT Aroom can be made to appear warmer or cooler, larger or smaller, and even as if it

had a higher or a lower ceiling, simply by the proper selection and arrangement of colours.

Tints and shades of red, orange, yellow, are known as warm or advancing Colours. Their use

in decoration produced a warm, cheerful and stimulating sensation and the visual effects of

advancing.

TO MAKE A LARGE ROOM APPEAR SMALLER Use warm Colours patterned wallpaper, make trim a different Color from that of the

walls. To make high ceiling appear lower: Use warm colors, drop ceiling with molding,

horders, or friezes. The wall design, if any should be in horizontal gradations.

Tints and shades of blue, green, and blue-green are known as cool or receding colors,

because that give a cool, quite, and restful effect and seen to present greater depth or

distance. A room treated in green is individual, restful and suggestive of the out-of-doors.

--2--

To make a small room appear larger: Use plain color for the walls, and choose cool

colors; paint the walls and trim the same hue.

To make a low ceiling appear higher: Use cool colors, vertical striped wallpaper.

LIGHT AND PIGMENT PRIMARIES Red, Orange, Green and Violet

Light primaries used for theatrical experiment with black background. Light

Primaries work up in value. When the beams of red-orange and violet overlap, we het a

luminous magenta-red or crimson. Violet and green super imposed yield blue, while red

orange and green yield yellow. And all three will produce white light.

The pigment primaries areBlue, Yellow and crimson red. In this the overlapping

obliques of blue and crimson-red yield violet. The blue and yellow yield green, and the

crimson-red and yellow produce orange. All three pigment primaries, when super imposed

produce black. This method is subtractive, or the negative use of color.

AFTER IMAGE An image retained in mind by the direct stimulation of the color of a visual object

after that object has been withdrawn from view.

Ex: concentrate thirty second or so on a green object, the withdrawn it from view and

immediately place a white card in front of you. That object then appears before you on the

card in complementary color (red).

JUXTAPOSITION Juxtaposition means the placement of colors side by side or close together. Each color

is affected by its surroundings and by light variations. For instance, yellow on a white

background seems dim compared to yellow on a black background. Grey on white looks

dark, whereas the same gray on black appears lighter.

OPTICAL ILLUSION Since red rays are less bent than blue rays, anyone is likely to misjudge the distance

of a red object and a blue object in juxtaposition. If two such objects are equidistant from the

eye, the red object is usually judged to be the nearer.

--3-- LEGIBILITY AT A DISTANCE

Legibility is the capacity with which a figure or shape can be recognized against its

background. Many experiments have been conducted to determine which color combinations

can be perceived at the greatest distance.

Color Combinations: Black on yellow

Black on Orange

Yellow- orange on navy blue

Bottle green on white

Scarlet-red on white

Black on white

White on Navy Blue

Yellow-Orange on Black

White on Purple

Purple on White

Navy Blue on Yellow

Navy Blue on Orange

Yellow On Black

ADAPTATION

The eyes tendency to reduce difference in the changing brightness and color of a

scene. On entering a dark room, the pupils of the eyes dilate to admit more light. Color

enables us to make accurate color judgements in vastly different lighting conditions.

ADDITIVE COLOR MIXING

When light beams of different colors are projected on to a white area, the light

reflected is a mixture whose color derives from the adding together of the colors of the

beams.

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ADDITIVE PRIMARIES

A set of colors that can be combined to form a wide range of colors by additive color

mixture, but not capable of being produced from each other.

BRIGHTNESS

An ambiguous term, meaning the intensity of a light source.

CHROMA

In the Munsell system, Chroma is the degree of saturation of a surface color. CHROMATICITY The color quality of a visual stimulus chromaticity makes no reference to the

brightness of the light. Chromaticity corresponds to the hue and saturation of the color

perceived by a standard observer under standard conditions of illumination.

COLORIMETER A device for specifying a color by matching it with a known stimulus that can itself

be specified quantitatively.

COLOURS The attribute of a visual sensation or by extension, an object or a light that can be

described by such terms as red, green, white, black and so on. The Colour Perceived as

belonging to an area depends on the composition of the light reflected from it, the

surrounding visual field and the state of the observer his expectations state of adaptation and

so on.

Perceived Colour has three basic dimensions:

Hue, saturation and lightness or darkness.

--5 COLOUR FULLNESS

A term coined by C.I.E (Commission International del Eclairage) as a synonym for

saturation or intensity as descriptive of Colour.

COLOUR SOLID

An imaginary systematic arrangement of Colours in three dimensions. In such

arrangements white and black are invariably placed at the top and bottom respectively of a

vertical axis; each Colour is placed at a height corresponding to its lightness (assuming the

solid is composed of surface Colours) at a distance from the axis (north, south-east etc.)

depending on its hue.

COLOUR TEMPERATURE

A specification of the proportions of light of various wavelengths present in a given

sample of light. It thus describes the overall Colour of the light and is not necessarily related

to the temperature of the light source. Thus to say that a fluorescent lamp has a colour

temperature of 4,500 degree K: (k=kelvins a scientific unit of temperature) means that it

gives out a whitish light resembling that emitted by whitehot body at 4,500 degree K: but

the gas in the tube is not actually at the temperature.

COMPLEMENTARY COLOURS

Pairs of light which when mixed together in the from of light beams, produce white

light; for example, blue light and yellow light of the right intensities will add to give white

light.

DISPERSION

The separation of light in to colours by refraction, more generally, the separation of

any type of radiation in to its component wavelengths.

--6

FLUORESCENCE

The emission of light following the absorption of light of shorter wavelengths. Thus

fluorescent paints absorb the invisible ultraviolet radiation present in sunlight and emit some

of the energy as coloured light.

GRAY

An achromatic Colour intermediate in lightness between black & white.

HUE

The attribute of A colour by which it is distinguished from another all Colour are

judge to be similar to one or a proportion of two of the spectral hues. Thus crimson vermilion

and pink though different colours are close in hue.

INTENSITY

The measurable brightness of a light source a synonym for saturation.

LIGHTNESS

The amount of white in a colour. Lightness is also the attribute of a visual sensation

by which an area is judged to transmit or reflect diffusely a grater or smaller proportion of

the light falling on it. Thus althought the brightness of a powder blue sweater may decrease

greatly when its wearer walks from sun shine in to shadow.

LOCAL COLOUR

A term used by artists to describe thetrue colour of an object seen in average day

light from near by, so that its colour is not affected by, for example distant, mountains look

blue although their local colour may be gray.

METAMERIC PAIR

Two surface or other light source that look the same colour to a standard observer but

the light mixtures they send to the observers eye have different wavelength compositions. If

the illuminant is changed, a metameric pair will usually appear different colours. The most

familiar example is a pair of fabrics that look the same under fluorescent store light (because

the mixture of wavelength in their reflected light stimulate the eye to give the same response)

but do not match in day light.(Because the compositions of the light reflected from the dyes

in the two samples have shifted and how stimulated the eye in different ways).

OPTICAL MIXTURE

The complaining of differently coloured lights by the eye to produce a new colour.

The apparent bending of the colours on a multi coloured spinning wheel (A kinetic colour

fusion disk) is an example. Blending of the dots in a coloured painting to give the impression

of a continuous range of coloures.

PIGMENT

An insoluble colouring material requiring to be applied to a surface in conjunction

with a binding material. Pigments coat the colour of the under laying surface rather than

combining with it.

PURITY

A synonym for saturation

Secondary colour

A colour obtained by mixing two or more primary colours.

Shade

In common usage a colour different slightly from a specified hue or colour.

In industry the term is used a colour obtained by mixing with gray or black.

STRUCTURAL COLOUR

Colour that is not due to the presence of some pigment or other colouring material, but solely

to the action of light upon the geometry of a transparent medium. Example are the iridescent

colours of an oil film or of the thin scale on a butterflys wings which change with the angel

of view.

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SUBSTRACTIVE COLOUR MIXING

The production of colours by mixing dyes or pigments or super imposing transparent

coloured filters:- The resultant colour is the result of the simultaneous or successive

substraction of various colours from the light passing through the combination.

SURFACE COLOUR

Colour belonging to a surface that sends light to the eye by diffuse reflection. The

perception of surface colours is strongly influenced by their context and by judgement

consigning their conditions of illumination.

COLOUR VISION

True colour shows in sunlight colour changes in artificial light no light: no colour

Colour speaks - stop, pass, peace etc

Colour works - focus, attract, repell, provoke etc

Colour impart - warmth/cool

Colour has volume - LBH (Length, Broad, Hight)

Colour set moods - depressed energized, sleepy, restful, angry etc

Colour has weight - heavy to light

In interior design these are applicable contextually

MUNSELLS COLOUR SYSTEM

Albert H.Munsell, American professor and colorist(1858-1918), created a colour

notation and system much used today by pgysicists and by various industries. His system is

an orderly sequence of colour presented three dimensionally in the general form of a solid

comprising a white and black apex, a neutral gray axis, pure hues about an equator, and

intermediate gradations of tints, shades, and tones in precise arrangement. According to

Munsell the three dimensions of colour hue, value, and chroma. His system follows the

general shape of a sphere; but because all pure colors do not have identical brightness or

purity,light hues like yellow are placed near the white apex, and dark colour link purple are

placed near the black apex also colour of strong purity of such as red-extend further from the

Neutral gray axis than colors like blue green. This feature makes possible certain flexibility

to the system, in case pigments of stronger purity should be brought out on the market. There

are nine value steps from black to white on the apex. Hue is delineated around the equator of

the sphere, value is shown up and down the vertical apex, and chroma is measured on a

horizontal plane from the apex outward.

OSTWALDS COLOUR SYSTEM

Wilhelm Ostwald, a German chemist and colorist (1853-1932), developed in a

somewhat similar system in the form of a double-cone solid. Ostwald set forth the principle

that every color seen by the eye is composed of varying proportions of hue,of white,and of

black and that all such components are measurable. The circumference of his double cone is

made up of twenty four chromatic hues, designated by numbers from 1 through 24. The

central pole presents a gray scale of eight steps, from white to black, each one designated by

a letter. In measuring brightness Ostwald found that the whitest pigment contains only 89 per

cent of white and the blackest black,96.5 per cent of black. So he has arranged the grays

visually equidistant in a geometrical ratio. His system of hue, white, and black as the

elements of color was a striking departure from older systems. His solid has a limitation , in

that its end points are at all times and cannot be extended in the manner of the Munsell

system.

VALUES

Light values -- White, Very Light Tint, Light Tint & Tint Neutral Gray is the Intermediate

between Black and White.

Dark Value -- Shade, Dark Shade, Very Dark Shade & Black

PRIMARY COLOURS

Set of colours that can be combined in a colour mixing process to produce a wide

range of colours, but two will together produce the third.

Eg: Red, Yellow, Blue

SECONDARY COLOURS

Acolour obtained by mixing two or more primary colours.

Eg: Green, Violet, Orange

TERTIARY COLOURS

Colours formed by mixing two secondary colours.

Eg: Olive, Russet, Sitron

LOCAL COLOUR

Aterm used by artists to describe the true colour of an object seen in average day light

from near by.

Distant mountains look blue although their local colour may be gray.

COMPLEMENTARY COLOURS

Pairs of colours which, when mixed together in the form of lights beams. Produce

white light.

Ex: Blue light and yellow light of the right intensities will add to give white light.

Red + Green + Purple.

SATURATION (PURITY)

A term used to describe the strength, or vividness of a hue. (The colourfulness of a

hue is generally known as its saturation)

Intense, pure or strong chroma, like the large circles.

Greyed, neutral or weak chroma-(see Tones)

Light, Whitish tint, high valuessee tints

Dark, blackish shade, dark valuesee shades

Warm advancing- see Top group of colours red, yellow, Orange

Cool, Receding see blue, Green and Violet colours.

SPECTRAL COLOURS:- The colours that appear in the spectrum of sunlight. (Newtons

theory) The ray of light, bent or refracted by passing through the prism. Produced the

beautiful and of rainbow colours that is called the solar spectrum.

Violet, Blue, Green, Orange, Red, Yellow, Indigo

VIOLET (PURPLE)

These are the high frequency variations of mystery and martyrdom. It show

discrimination and tend to suggest things mysterious and occult. In its lower variations, violet

denotes penance and melancholy.

BLUE

Blue is the spiritual colour, associated with sky and water, being clear cool and

transparent in quality. It is found to be the most soothing, subduing and cooling colour,

leading the mind to thoughtfulness and delibration.

GREEN

This is natures colour associated with outdoorscool, fresh and rejuvenating in

quality. Psychological tests provide it to be a tranquil colour for eg: Hospitals Being cool in

nature it helps to overcome the physical discomforts of high temperatures. Green is the

vibration of individuality, manifestation, and the essence of things personal possession and

wealth.

YELLOW

This is an enlightening vibration. The cheerful, brightening colour of light and

wisdom. The hue transcends the intellectual and reaches up in to the realm of intuition high

spirituality, and intelligence. Yellow the hue of highest visibility.

ORANGE

Orange is a thermal colour of warm invigorating quality. Its vibration of vitality and

strength is suggestive of the living pulsating life force.

RED

This hue is stimulating and exiting; it is suggestive of heat and heart beat. It has a

physical vibration that stirs the emotions.

The more cheerful phases of this hue include warmth, joy, pleasure, and sense

stimulations. Because of its striking, aggressive visibility and compelling vibration, red is

universally accepted as a danger signal.

COLOR CIRCLE (COLOUR WHEEL)

As a matter of convenience, colorist, reproduced the spectral band as closely is

possible with coloring materials, adding the missing purples, to form a colour wheel or color

circle.

The equilateral triangle points to the three fundamental pigments.

A-- Primary

B-- Secondary

C-- Tertiary

Perspective is an optical effect which makes things close to us larger than the same object

viewed at some distance.

ADDITIVE COLOUR MIXTURE

When the three additive primaries, red, blue and green are mixed in proper

proportions in the form of overlapping beams of light, white light is produced.

If any two lights can be mixed to form white light, they are called complements or

complementary hues. White light can be therefore be produced by adding any primary and its

complement in the proper proportion.

Complement of Green -- Magenta

Complement of Red -- Cyan (Blue + Green)

SUBTRACTIVE COLOUR MIXTURE

A transparent object such as a film or filter, looks coloured if it transmits light of a

certain wavelength selectively and absorbs or subtracts its complement from the incident

light.

If light is passed in succession though two filters of different colours, each will

subtract the complement of the colour that it transmits. This is sometimes called subtractive

mixture. For instance, if white light is passed first through yellow filter and then through

cyan filter the transmitted light will look green because the yellow filter will subtract blue

light and cyan filter will subtract red light from the incident white light.

This shows that if white light is passed through a pair of filters yielding any two of

the three subtractive primaries, cyan, yellow, magenta the transmitted light will match the

corresponding addictive primaries , red, blue, green. If white light is passed in succession

through filters of the three addictive primary hues each absorbs light in two thirds of the

spectrum and the result, will tend towards black. Ina a very general way the subtractive

primaries are the complements of the addictive primaries. They are yellow (minus blue)

Magenta (Minus green) and Cyan (Minus Red).

OVERLAPPING COLOURED FILMS