Colour theory

  • About colour

    These exercises may be carried out in any medium including digital, however if using physical paint I recommend gouache, acrylic or oil paint on a smooth surface. Texture and other surface artifacts should be avoided. Size is your choice, A4 is plenty for any of these.3DIMS

    1. Tonal Scale

    To help you understand this concept, make a tonal scale with as many even steps between black and white as you can. Steps must be butted up against each other with no space or lines in between. While very simplistic, this actually becomes a rather useful tool for subsequent exercises and other purposes.

    Tones should be flat, clean and opaque with a strip along one side with which the scale can be held and a flush edge on the other.

    Hint: Prepare the scale from pre-painted “chips” which can be pasted down in the right order… and if you have trouble doing this… maybe we need to talk!


    2. Controlling the dimensions of colours: Get some control

    Create three paintings, each of which varies in only one dimension at a time. That is,

    1. in Tone where saturation and hue remain constant
    2. in Hue where saturation and tone remain constant; and
    3. in Saturation where hue and tone remain constant.

    Restrict the influence of other factors… e.g. texture, gloss, transparency. Use plenty of imagination but keep design simple.

    2a. Colour Maps (some 2d and 3d colour models)

    3. Applying an understanding of Tone in Chromatics

    A strip or section of a pure monochrome is faithfully converted to full colour in a divisionist technique*. Should involve a good range of hues and must adhere accurately to the tone underneath. This can be made easier by using your tonal scale! The “base” tone should be visible for comparison.

    Understanding the principle of this exercise will quickly convert a good sense of tonal composition into a much more powerful and comprehensive skill. If you don’t already have a pure monochrome picture to work with… now is the time to experience the value of making monochrome preparatory works for later full colour pieces.

    * Of small separate marks.

    4. Atmospheric Perspective

    This really useful and often overlooked device is made easy by your knowledge of basic colour theory. It’s really just the conscious use of contrast across a picture plane to deepen focus, focus the pictorial drama and dramatise the illusion of depth.

    From a base “atmosphere” create an image which derives its depth from the use of atmospheric perspective. Prepare the colour range beforehand. Try to restrict the effect of other cues such as linear perspective, obscuration etc. You could use any arrangement of objects in space as a vehicle to produce a sense of greater depth and “atmosphere”.

    Hint: This exercise is often confused with 2(c); Contrast ratios (the issue in colour perspective) can involve any or all of the colour dimensions.

    5. Colour in Shadow

    This exercise must be done physically rather than digitally.

    1. Form a linear hue scale (from subtractive colour circle) at home values but somewhat tinted up.
    2. Arrange a simple object such as a ruler to throw a shadow across all the colours in the scale in natural daylight. Something like this (but full chromatic of course)
    3. Make an accurate painting of the arrangement. Do not make assumptions about what might be required to mix the shadow. It may not be the same for each hue either. This is not intended to be accomplished by a transparent wash of dark across the colours to create the shadow, but by accurately and opaquely mixing each colour in the shadow in its turn. Understanding what constitutes the colour in the shade will require some thought about the light source/s.

      The Dimensions of Colour

    6. Dealing with simultaneous contrast


    Colours A and B are “islands” in “seas” of X and Y colour.

    Make colours A and B slightly different in fact.

    Adjust colours X and Y until A and B appear the same.

    This exercise can be done at several levels of difficulty. Remember there are at least three dimensions of colour. You can examine the simultaneous contrast effect in one dimension at a time…. or more. Meaning the difference between A and B could be one of say, tone only or perhaps more complicated. If tone is the only difference, the solution (colours X and Y) needs only to be tonal (perhaps literally just black and white). If additional dimensions are involved, the solution will involve the additional dimensions. The point of this is not so much in solving every imaginable difference as in really understanding the effect.

    Hint: don’t make A & B fully saturated colours.

    Hint: When mixing colours that contain white – always start with the white in the predicted appropriate total volume and add the other colour(s) little by little to the mix. The other way round will generally exhaust your supply of white paint in no time!

  • A Few Extras



    A diagramatic representation of the wavelengths/frequency distributions present in a dark grey, a brown, a light grey, white and a blue.

    A range of colour progressions, vertical and horizontal (ordered sequences in hue, saturation and tone)

    Anomolous lines of admixture.

    When mixing a “pure” red and a “pure” blue one is supposed to get a “pure” violet. Of course this does not happen. What you get is the muddy grey/purple. The same applies to a greater or lesser extent with the other so called primaries. The closer together colours are on the circumference of the colour circle the more “pure” their resultant mixtures. For this reason you need as many fully saturated colours as you can get or afford, that is colours at or close to the circumference.

  • Atmospheric perspective

    The atmosphere “base” here is RED (contrary to the customary blue-violet). Things appear closer to the picture plane by the degree to which they vary [in this case in saturation (and back to front)] from the base atmosphere. Everything else being equal, warm colours normally seem to project forwards and less saturated colours appear to recede. I have done it this rather perverse way to show that understanding of the principle is better than using an old formula. You can sometimes see such an atmosphere in a bushfire or on a dusty day at sunset.

    The checkerboard image simply shows the colours used in the atmospheric picture on a red base. If you can get an atmospheric effect from such unlikely colours... how much more so can it be done if with more appropriate ones, not to mention all the other cues of perspective?The checkerboard image simply shows the colours used in the atmospheric picture on a red base. If you can get an atmospheric effect from such unlikely colours… how much more so can it be done if with more appropriate ones, not to mention all the other cues of perspective?


  • Colour Maps

    Section of a 3D Colour Solid

    A cutaway section of a solid based on the equatorial saturated colour circle model.

    The Plumbob Colour Solid

    This solid which I have named the Plumbob is structured around an "equatorially" located saturated and subtractive colour circle. It diminishes to the top and bottom to reflect the decreasing ability to discriminate differences between colours as they darken or lighten.

    12 Colour Subtractive Circle

    A 12 hue subtractive colour circle arranged in opposed complementary pairs, and saturation increments.

    Lines of Saturation

    Lines of admixture showing saturated colours on the circumference and degrees of desaturation proceeding towards the centre.

  • Home value

    Home value or home tone: The Tone or Value of a colour at full saturation

    This diagram indicates the relative tones of different hues … unlike other colour diagrams (colour solids or colour gamuts) such as my Plumbob Solid (see colour maps) which suggest that all saturated colours can be aligned with the grey (a middle grey) to which they are opposite on the tonal centre shaft.

    The significance of the Home Values of colours should not be underestimated. Painters often forget that in their most saturated state hues vary widely in Tone. For instance, compare the tone of saturated yellow to that of saturated blue. Then when mixing colours these differences play a big part in the resultant colour. Secondary or tertiary colours are often darker than anticipated. However when you know this is to be expected… you can allow for it.

    In the next diagram you can see what can be expected when for instance you mix complementary colours together. The amount of darkening is indicated clearly. The line of (subtractive) admixture between two “colours” is a line not just across hues but also across tones and under almost all circumstances across saturations as well.

  • Hue

    This is an attempt to use all the hues in the bar at the bottom at the same tone and saturation. The third bar from the bottom contains all of the colours at the tone and saturation used in the diagram.

  • Saturation

    The saturation line from a magenta to grey. The colours in the line underneath are all those in the design above.

  • Tone

    This is simply an example using the line of tone up and down from red.

  • Tone in chromatics

    On the right you can see the all hues I have used arranged in the "globe" in the same tonal or value order as in the "tree". No chromatic mark may be lighter or darker than the grey upon which it sits.

  • Simultaneous contrast

    At the top is how this exercise might appear with the outer flaps shut. Below one can see how it could be constructed so that you can easily test the colours for similarity.

  • Terminology

    • Hue: Different hues have different wavelengths/frequencies and are normally represented around the circumference of colour circles.
    • Tone: How much light there is (how light or dark a colour is) irrespective of its hue or saturation . Generally represented in a vertical scale.
    • Saturation: A measure of the predominance of any one frequency over others in a colour appearance. (Can be thought of as purity, vividness). Normally represented radially on a colour circle from neutral grey in the centre to fully saturated at the circumference.
    • Value: another name for tone (USA)
    • Chromatic content another name for saturation
    • Home Value: click for a better understanding of this important term.
    • Intensity: Your guess is as good as mine.
    • Brilliance: Probably a measure of both lightness and saturation… but open to individual interpretation, therefore not very useful as a common term.
    • Complementary colour: colour with whose complementary pair a neutral grey can be mixed or produced as an after image.
    • Contrast: of which qualities, dimensions or attributes? … That is the question.
    • Tint: a colour with white added.
    • Shade: a colour with black added.
    • Simultaneous Contrast: the effect that (by virtue of the influence of the after-image process) produces “deceptive” but predictable colour appearances.
    • Harmony: room for an essay here. What would you say?
    • Discord: ditto
    • After Image: the “ghost” appearance of a colour’s complementary, when after prolonged exposure a colour stimulus is withdrawn or shut off.
    • Colour: a comprehensive term involving at least three dimensions of visual appearance (hue,saturation,tone).
    • Primary: a colour which cannot be mixed from others. Except in a rather simplistic sense this is not a very useful term without a comprehensive contextual understanding.