Colour: How Do We See Colours?
Colour: How Do We See Colours?
Colour: How Do We See Colours?
Colour
How do we see colours?
We see rainbows when it rains because the white light of
the sun's rays goes through the raindrops and splits into
seven colours. These are the seven colours of the rainbow.
The colours of the rainbow are red, orange, yellow, green,
blue, indigo and violet. These colours are called the colour
spectrum.
Coloured objects are only a visual impression. The colour is
produced in our brain. All objects transmit a sense of colour
because their surfaces absorb white light and reflect the colours we see.
When light shines on an object, the surface absorbs all or part of that light. The part of the white light
that is not absorbed by the surface bounces off the object, changes direction and this produces the
sensation of colour.
Mixing colours
Coloured lights
Some colours are more important than others because we can obtain all other colours by mixing them
together. These are called the primary colours.
If we can separate white light into the colour spectrum, we can also reverse the process. White light is a
mixture of all coloured lights. However, we needn't use all the colours in the rainbow to make white
light.
Primary lights
There are three colours of light that are
called primary lights because all other
colours are obtained from them.
They are basic colours that cannot be
made by mixing. These lights are blue,
red and green.
To get white light, we only need to mix
these three primary lights: red + blue +
green = white.
Secondary lights
We can obtain secondary lights by mixing
two primary lights. Primary and secondary
lights are the basic colours of light.
Blue light + green light = cyan light; blue
light + red light = magenta light; red light +
green light = yellow light.
Departamento de Dibujo IES Rodrigo Caro Sección Bilingüe
Colour pigments
All the paint colours that exist are made from coloured powder and a binder (agglutinant). Depending
on the type of binder we use, we can create different types of colouring tools: watercolours, crayons,
pencils, markers, pastels, etc.
These coloured powders are called pigments. They can absorb and reflect parts of white light.
Primary pigments
To produce the colour black, we can mix all
the pigments together, or just the three
primary ones: cyan, yellow and magenta.
These three colours are called the primary
pigments because you cannot get them by
mixing other colours and because all known
colours can be obtained when these three
are mixed.
Secondary pigments
When we mix two primary pigments we
obtain a secondary colour.
Cyan pigment + yellow pigment = green;
magenta pigment + yellow pigment = red;
cyan pigment + magenta pigment = blue.
Vincent Van Gogh. Streets in Saintes-Maries. 1888. Franz Marc. Large Blue Horse. 1911.
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Colour families
A simple way to classify or choose colours when creating a work of art, is to separate them into
families. Colours with similar tones belong to a colour family.
Blues
Colours with cyan in more than half of their mixture
belong to the blue family.
Reds
Colours with red in more than half of their mixtures
belong to the red family.
Yellows
Colours with yellow in more than half of their mixtures
belong to the yellow family.
Carlo Carra. The Red Horseman. 1912. Red is the dominant colour here.
Each tone has a different amount of magenta. Van Gogh. Fifteen sunflowers in a vase. 1889.
Look at the different tones of yellow in this work.