Topics of Content:☺History & Science of Colour Theory☺Primary Colours

☻Additive Colour☻Subtractive Colour☻Traditional Primaries

☺Pigment Mixing☺Fun With Optics☺Impressionism & Pointillism

Art 10, 20, 30

History of Colour Theory

• In the arts of painting, graphic design, and photography, colour theory is a body of practical guidance to colour mixing and the visual impact of specific colour combinations. Although colour theory principles first appear in the writings of Alberti (c.1435) and the notebooks of Leonardo da Vinci (c.1490), a tradition of "colour theory" begins in the 18th century, initially within a controversy around Isaac Newton's theory of colour (Opticks, 1704) and the nature of so-called primary colours.1

The Nature of Colour As Light• Light, the Eye, and Colour

For most of us, the perception of colour occurs so easily and naturally that it seems to suggest that colour resides fully and directly in the objects that we see. In fact, colour perception is the creative act of our uniquely configured visual system.

Colour does not exist in objects. Colour is light that is reflected off of an object, through our eyes, and perceived by our brain.

Light is Colour, Colour Is Light

Light is Colour, Colour Is Light

The visible spectrum of light is the portion of the electromagnetic spectrum (energy waves) that we can see. We are blind to all the rest.

The visible spectrum includes red, orange, yellow, green, blue, indigo, violet (ROYGBIV).

Colour exists as light waves that enter the eye, and are interpreted by the brain.

Light, the Eye, and Colour

• Colour does not exist in objects. Colour is light that is reflected off of an object, through our eyes, and perceived by our brain.

Colour does not exist in objects. Colour is light Colour does not exist in objects. Colour is light that is reflected off of an object, through our that is reflected off of an object, through our

eyes, and perceived by our brain.eyes, and perceived by our brain.

Oh, it’s green!

Objects and pigments reflect some colours of light, and absorb other colours. The colours that the pigment reflects are the ones that reach our brain through our eyes, and therefore we perceive the object to be that colour.

Pigment: a substance used as a coating to protect or decorate a surface (especially a mixture of pigment suspended in a liquid); dries to form a hard coating; "artists use 'paint' and 'pigment' interchangeably"

Why do objects appear coloured when most objects are not sources of light?

The Experience of Colour as PigmentColour Pigment perception can be described in terms of three dimensions: hue, brightness, and saturation. These three dimensions can be represented in simple terms as a spindle-shaped "colour space."                                               

The hue of a colour refers the colour name (e.g., red or blue), and is a function of the wavelength(s) reaching the eye.

Brightness refers to the intensity of a colour, and is roughly proportional to the amplitude of the incident wavelength(s).

Saturation refers to the "depth" or "purity" of a colour, and is related inversely to the number of different incident wavelengths. At the brightness extremes (i.e., black and white), the spindle comes to an infinitely small point, indicating a lack of apparent hue and thus complete desaturation.

Primary ColoursPrimary Colours: are the colours from which all other colours can be made.

As young children we are taught that there are 3 primary colours: Red, Yellow, and Blue. These are called the Traditional Primary Colours.

There are three sets of primary colours. There are the traditional primary colours, there are additive primary colours, and there are subtractive primary colours.

Although these traditional primaries can be mixed to create thousands of other colours, Red, Yellow, and Blue cannot be mixed to create all other colours, and so technically they are not really primary colours.

However, they are very close to actual primary colours, and they work relatively well for mixing paints and other pigments. The traditional primary colours have been used for hundreds of years to mix and create other colours, and are the primaries artists like Leonardo Da Vinci would have used to mix pigments.

Additive vs. Subtractive Colour Mixing

Additive Colour MixingAdditive Colour Mixing: is the mixing of colours of light.

The human eye uses the method of additive colour mixing to perceive colours.

With additive colour mixing, the primary colours are Red, Green, and Blue (RGB).

If all three primary colours are mixed together, the result is white light (all colours).

Red + Green + Blue = White

Mixing different amounts of each colour can create millions of different hues of colour.

ei. Red light + Green light = Yellow light

When none of the primary colours are present, there is black (no light, no colour).

Additive Colour MixingTelevisions, computer monitors, LCD projectors, and most other colour displays use the method of additive colour mixing to create millions of hues of colour.

Additive Colour Mixing

Subtractive Colour Mixing

Subtractive Colour Mixing: is the mixing of colours of pigment.

With subtractive colour mixing, the primary colours are Cyan, Yellow, and Magenta (CYM).

The more these colours are mixed together, the less is reflected to be seen by the eye. (More waves of light are subtracted from what is reflected back to the eye.)

If all three primary colours are mixed together, the result is black (the absence of light). No light is reflected back from pure black objects.

Cyan + Yellow + Magenta = Black

When none of the primary colours are present, there is white (all light reflected).

Subtractive Colour Mixing

Mixing paints is different from mixing light. If we start off with two tins of paint – say cyan and yellow – and shine white light at them, then each of the paints absorbs some of the colors from the white light and reflects others. If we now mix the two paints together, they each continue to absorb the same colors that they did before, so we end up seeing whichever colors neither of them absorbed, which is green in this case. This is why we say mixing paints is subtractive, because the more paints we mix together, the greater the number of colors the combination subtracts from the white light.

Traditional Primary Colours

Some of the pictures that follow can cause dizziness or might possibly cause epileptic seizures. The latter happens when the brain can't handle the conflicting information from your two eyes. If you start feeling unwell when using this presentation, immediately cover one eye with your hand and then leave the page. Do not close your eyes because that can make the attack worse.

The next few pages contains some works of "anomalous motion illusion", which might make sensitive observers dizzy or sick.

Fun With Optics

Akiyoshi's Illusion Pages

Pointillism

Pointillism: is a style of painting in which small distinct points of primary colors create the impression of a wide selection of secondary and intermediate colors. The technique relies on the perceptive ability of the eye and mind of the viewer to mix the color spots into a fuller range of tones.

A postimpressionist school of painting exemplified by Georges Seurat and his followers in late 19th-century France, characterized by the application of paint in small dots and brush strokes.

PointillismAdditive colour mixing can also be used as a technique in art. In this

technique called pointillism, small dabs of paint are placed adjacent to one another to produce a brighter, more vibrant work. This form of art was influential in France, Holland, and Italy in the 1890s and 1900s.

The image shown here is a pointillist rendering of a summer scene at a beach. When viewed from a distance so that the dabs of paint cannot be discriminated, a somewhat different global perception of colour results. Even when the colour dabs can be seen, pointillist paintings tend to be more lively and luminous than those based completely on subtractive mixture.

Pointillism

Pointillism

Pointillism

Pointillism

Pointillism

Terminology• Pigment, Hue

• Trichromatic

• Visible Spectrum - ROYGBIV

• Additive - RGB

• Subtractive – CYM

• Traditional – RYB

• Pointillism

Colour Mixing Wheel: Primary Colours Secondary Colours Tertiary Colours Complimentary Colours Analogous Colours

Art 10, 20, 30