A guide to perception (how we view colours)

Is colour a Psychology or a Science?

- What it is - and how we can describe it better (or at all)..
- Is it a SCIENCE or an ART?
- Digital Colour systems
- What is the COLOUR we had in mind?
- How to match colours better.
- Limitations for DIGITAL Photo
(and print) colours.
- Do we see colours as they are
(or does our mind set the colours from memory?)
- Colour Psychology, are we affected by colours, if so how?
- Do animals see the same colours as we do?

How can we describe it?
Colour is a huge and important subject that leads us to enquire 'as to the nature of colour' and it's discovery
(or should I say recognition) by Issac Newton (of his work on 'The OPTIKS' 1704) that COLOUR is actually part of natural sunlight. He proved that sunlight can hold a rainbow of colours and each colour was clearly definable into it's component parts: Violet, Indigo, Blue, Green, Yellow, Orange and Red. You can see this yourself should you ever purchase a 'Newton-Prism' and via a narrow slot cut into black card and by shining a bright light through it and place a white card angled to the prism you will see the Rainbow of colours exactly as he described.


An Interactive demo explaining Newton prism can be found here:

You may ask why just seven colours
(when there are perhaps clearly more colours to be seen)?. This can be explained as our cultural heritage, seven was a meaningful number, the number 7 having a religious significance to unlocking the secrets of the Universe. It is still a good number to start with, as clearly Infra Red and Ultra Violet colours remain invisible to us and yet are so important in other areas of life. Infra Red keeps us warm and Ultra Violet, although we cannot see it directly, it has enabling properties in making colours appear 'brighter' than they would otherwise be. i.e. Fluorescent.

So there are 'invisible colours'. But from our own perspective the colour we cannot see are less interesting than the ones we can see here. Any 'invisible colours' would take us into the new discoveries of X rays, Cosmic Rays and particle Physics which although interesting - is beyond the scope of this article on colour. I want to keep the Physics simple here. No wavelengths.

How we describe colour is both personal and cultural. We are all more emotional towards certain colour. It does (in part) - define us as a thinking species
(other animals may have other colour requirements to survive) and our attitudes and preferences and misfortunes, our hopes and even our desires are tied up in how we interpret colour and how we live in our real world. Advertising relies on your response to it.

For example it is not so long ago that PINK was seen as a 'Boys colour' and Girls wore 'BLUE'.
Although colour Photography was not around at the time of the Victorians but you can see a reference to that in this excerpt:
here, (and no doubt you will find more gender specific colours of the period on Google if you are interested in just that aspect).

I will talk more on this later as I wish to explain why Newton identified only seven colours (
there are of course more), but seven is a number that we remember more than most for mainly cultural religious reasons, 7 is significant number. Newton's "philosophical discovery" was the realisation that white light is composed of a spectrum of colours. Newton realised that objects are coloured only because they absorb some of these colours more than others.

Newtons's discovery eventually led to a scientific appreciation that all colours exist in pure white light. An equal distribution of colours will therefore create a pure white light by explanation.

Newton is remembered for his own useful
colour-wheel as an easy to remember colour reference (he was vilified at the time in Germany for producing an inaccurate colour palette - as it did not match an Artist's colour palate which was considered an 'obvious error to make. However a better understanding of prevailed as 'reflected colour' from pigment and and transmissive colour from light were indeed different and shown to be different and treated as Additive colour (pigment) and subtractive colour (light).

The Newton Colour Wheel (below) is a very useful reminder of the relationship of colours.

SatColorWheelwatercolour SatColorWheel2 ColourWheel
Top Left: Newton's colour wheel (top left) made all the colours as relationships with each other.

A guide to Digital Photo colour

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Red + Blue = Pink


LIGHT colours of pure white light are 'subtractive' in that when colours are mixed they are lighter than there component parts. So if we take our Red and Blue swatch we create a lighter (light) colour.
RED (R204/G0/B0) BLUE (R0/G51/B255)

(So adding lights Red and Blue creates a lighter colour) .


Red + Blue = Mauve


Above Middle: Newton could show that varying any colour can change the density or brightness of that colour
Top right: Newton devised a simple colour chart of seven colours (Violet/Indigo/Blue/Green/Yelllo/Orange and Red.) Seven is an arbitrary number of colours.

I should add quickly that paint colours are very different to reflected colour of light (as used by Photographers). So there are actually two different colour wheels. And the difference can be very marked. To illustrate this two colours are compared below. One as Light and another as Pigment colour:

PIGMENT Paint colours are 'additive' when colours are mixed and therefore Red and Blue swatch create a Mauve pigment.
So adding pigment Red and Blue creates a darker pigment colour..

RED (R204/G0/B0) BLUE (R0/G51/B255) * RGB to paint conversion blend made in PhotoShop.

To illustrate this better try varying the strength of just three basic Primary (Red/Green/Blue colours.
Varying the strength of each of the RED/GREEN/BLUE colour in turn (below) in this interactive example.

With thanks to Bo Hjort Nielsen for creating this RGB test bed in Livemotion flash

By adjusting just three 'primary colours'
(shown above) strength in the RED, Green and Blue channels we can create the 'secondary' colours in the colour wheel. This does not work for pigment so even if you matched the colours, any colour prints are by definition only approximate and that remains the problem to this day for many professionals. More on importance of colour profiling here.

I.e. Colours you can see on screen, may not be printable and varies to each colour print process. It is an Art and a Science getting colours to match consistantly (otherwise it's expensive trial and error!).

So if your a photographer, the slightest change of lighting can have dramatic effects. How many of us are conscientious of a colour hue that changes thought a normal summer day? The colour of morn (reddish tinge) to midday hot (yellows) and back to Sunset (reddish tinge). Indeed it is to an experienced Photographers eye that a photograph can tell at whet time of day a Photograph was taken by the colour hue. Artists have long since appreciated the subtle blend of morn colours to that seen later midday.

This is, of course, the position of the sun and how it is deflected at low angles of sunrise and sundown and when it is at its zenith in the sky it's colour is at it's shortest path through the atmosphere. The shadows are obvious on a bright and sunny day, and less so on a cloudy day when the shadows are soft and colours subdued. Yet we perceive colours exactly the same.

We cannot discount our own psychology when we view colours either. Our mood changes according to light intensity and colour and we paint our homes to (hopefully) reflect our moods and aspirations.

We cannot control the Clouds, shadows of trees or rain, but only our own unique environment Only a Photographers studio can you accurately control colour and exposure and detail. And even then there is a 'built-in' colour bias when using film (i.e. Fuji Velvia or Kodak Extachrome) and the digital back of the camera has colour profile as a 'signature' if of you were to analyse light projected and light recorded. This is usually called a ICC colour profile and changes from device to device.

Although we strive for colour accuracy
(most obvious in colour branding and packaging shots) the actual colour we see does vary naturally otherwise. This variation of our own eyes, our spectacle lenses (or tints), our overhead lighting (even if colour temperature calibrated), the curtains/blinds in a room, the colour of our wallpaper, painted walls are reflected as influences to our overall colour judgement.

Note: Photographers will use a light box to mask out possible colour reflections and paint the studio white for that practical purpose. It is however it is still a matter of judgement.

A lot of technical detail goes into colour matching across devices whether it is a scanner, camera, printer or flat screen LCD, PLASMA, CRT in the form of (ICC) colour profiling and 'look up' tables to colour match from one device to another in the form of some standardisation. But not all devices match or agree.

A typical example may be the adobe (RBG1998) colour space (used in professional printing) and the sRGB colour space show below which has become the photographers default. This is only for comparison (other colour spaces are available for other print processes and film specifications).

Adobe98 sRGB

Top left Adobe RGB 1998 colourspace and top right sRGB (digital Camera default). Detailed analysis here:
Note: you can find your own 3D colorspace comparison (Mac 10.3 to 10.6 colorsync utility)

The quality of colour has so much importance because it affects us so. Not obviously perhaps at first. After all black and white photography predates colour photography and even in that, possibly more skill is required to balance a black and white photograph than a colour one
(there are various photoshop techniques to do this and 'desaturate' is not one of them).

True colour rendering is a mind subjective phenomena we learn. We think we know all about a colour because we have seen it before, but we are all very poor at colour judgement (when outside our own environment). If the blind 'see' colours in their minds as we do then this begs the question what is the colour? A feeling? a perception or just a description or a word 'Green'. If you had never seen the colour sky blue would the sky still be 'Blue' for instance?

You can see that we are moving away from Newton's observations of what a colour is - to what it does or seems to do for us the viewer. Our eyes are also more positively charged towards Reds and Blues than other colours and let us not forget that 'Black' is not in fact a colour at all. That black of your computer screen is not even a 'Black' but very likely - a very dark Green. (TV Video colour is notoriously unreliable as can be seen from many past web sites that restrict themselves to '216 colour table' so called web colours restricted by the mass produced video monitors of the 1980's and even to some existing flat panel displays).

Even with increased video resolutions (a such now exist) the colours from one video screen to another do not match one another
(and any visit to any TV shop will in all probability display various models all with a marked colour/contrast variation to prove that point). At best you can adjust the colours yourself to match your preference but that is really the point. Colour differs on each device.

Professionals' would use a colour '
target' to match a new screen. There are a number of ways to do this. Despite the video screen only showing a relatively small range of colours (often quoted at 16 Million colours is an improvement over 256 colours) and the perception is that colours are 'true' colours when they can only ever be 'approximate' even on the best and most expensive screen. Accuracy is really experience and value judgements and not the equipment per se. A cheap monitor will of course be totally ineffective, as well as strain your eyes with it's poor detail resolution. Most (home) Internet Monitors and TV's do however fall into this bracket.

(A screen shot of two different monitors/TV would help illustrate this, but you get the picture)

Its a dilemma that all the colours we see, are interpreted differently and yet we all seem to agree what those colours actually are. Even when seen underwater, midday, mid morning, poor light, bright light, we make a very good 'guess' at the proper colour. Even a black and white photograph can be coloured
(in our minds) with a good indication of where the colours are and how bright or subdued they are.

So colours are not 'seen' but rather interpreted through a unique 'understanding' process that differs only slightly from one person to another. It is as if we are programmed with a range of colours and preferences that even if not perfect are more than adequate.

To illustrate this aspect it is worth exploring the many visual puzzles that exist highlighting colour anomalies (below). Colour can appear to change inexplicably. To illustrate this point the link below is a fascinating video via youtube of an effect
(occurs in greyscale shadows) of a well known and surprising colour changing phenomena:


Video by Brussup:
If you cannot see above the video link. Click picture for link in new window.
In this video clip the grey squares illustrate (midway break point in the grey scale point of a black and white image) can alter our perception of where the colour is. In this case a simple black and white image in shadow. You would think this is unique until you discover that it applies to colour as well (see below).

Lotto cubes

In these two pictures you can see how our colour vision adjusts itself automatically. It only looks odd when you compare the two coloured squares and discover that two distinct colours are actually the same colour (on both pictures)!

insert: The above pictures are reproduced for illustration and are credited to the research of Lotto labs in London
Image credited to Dr Beau Lotto (image link

Colour can be measured in great detail yet how colours 'relate' to our senses and intelligence can only be guessed at. However a trained professional who knows the print process can ensure a consistent colour reproduction through (ICC colour profile) experience and colour proofing. However as can be seen in this article -
colours do naturally change according to your viewing conditions - and our eyes do a pretty good job adjusting even under extreme lighting conditions such as artificial light and constantly varying cloud conditions etc.. Just viewing your Camera shots 'over' and 'under' exposure clearly shows that daylight is constantly changing. Artists seem to have this ability (even without a camera) of capturing a fleeting feeling, a mood by careful and patient observation of our environment.

So why do Dog's dream in Black and white
here? (untrue I suspect, other mammals may interpret colours differently, (and even our cultural language seemd plays a part in our own chosen vision not always shared by other cultures as 'colours' agreeable or even 'recognised'). And yet some colours seem to come from our memories (with or without sight). It's a human enabling feature but without a point of solid reference, colours can become a figment of our imagination based on how we 'feel' at the time.

As colours naturally vary; then our mood is sensitive to colour. It has even been suggested that colour can automatically change our mood at will.
Why would we decorate our homes if this were not so?

(the above link at top of page) that Boys' or Girls' are taught colour awareness but they also seem to have inherited colour awareness at an early age when parents notice that they have a strong preferences in terms of colour and attitude. This then gives us our colour guides for 'Toys' which we as parents buy for our children. Bright primary colours proliferate, perhaps subtle colours are learnt later.

I think I will leave it there for you to ponder the true meaning of COLOUR!
and I shall leave you with this single puzzling thought....

In a dark unlit room. Do COLOURS still exist? (Discuss)

I hope you have enjoyed this article.
Colour is a fascinating study subject.

Article by Philip Searle

See also: BBC Tv Horizon (from 2011);
'Do you see the same colours as me?' here
See also: A detailed guide to Colour making attributes
See also: More dimensions of colour here:
See also: Subtractive and Additive colour
See also: More on Isaac Newton
See also: An overview supporting the Wheel of Colour'
See also: How lighting effects vision :

Last update 19th October 2012

Copyright 2012 Art Services