In my previous posts about colour theory I talked about the different colour mixing models (RGB, RYB and CYM(K)) that are used to understand the way all the different colours can be reproduced and , related to the acrylic pouring technique, why colours become sometimes neutral or muddy if mixed.
In this and my next post I'd like to make a step backwards in the colour theory and talk about the term colour, all its properties and how we can use it to create wonderful colour palettes.
What is a colour? A definition.
The colour is the visual representation of each individual component of light responding to a specific wavelength. Each wavelength corresponds to a colour and is also how our eyes perceive the environment and objects around us, depending on how each object absorbs and reflects light.
These are the individual wavelengths.
Colour Terms from the Colour Theory and Colour Properties
According to the colour theory, colours have perceiving properties such as hue, value and saturation, so that each colour can be explained/described as a 3D-concept as a result of the interaction of all three dimentions.
Hue
The hue is the pure colour or the pure pigment without added white or black. This corresponds to the basic colours which are on the colour wheel or the rainbow: yellow, orange, red, purple/violett, blue, green plus the in-between colours yellow-orange, red-orange, red-purple, blue-violett, blue-green, yellow-green.
White, grey and black are considered neutral colours and no-colours (no-hues).
Chroma of a hue
The term chroma is strictly connected to the hue and is a measure of the purity of a colour. The highest degree of chroma is reached if a colour has no white, grey or black mixed to it. In-between and lower degrees of chroma are obtained through desaturation of the hue by adding white, grey and black.
Value
The value is a measure of the luminosity or darkness of a colour. The value of a colour can be changed either by adding white (light) or black (dark shades).
Saturation
The saturation is a measure of how bright, intense or pure a colour appears, according to the quantity of grey contained in it. The saturation of a colour can be changed by mixing white, grey, black or a complementary colour to a hue.
From the interaction of hue, value and saturation we can have three different possibilities:
Tints, if we mix white.
In this case we will get lighter (but not brighter) versions of the colours which are also called pastel colours. The hue remains the same but the adding of white desaturate it.
Due to the fact that white has a strong colour strength you should create tints starting from the colour hue and adding little by little the white until you get the desired colour.
Tones, if we mix grey (neutral colour).
In this case we will reduce the brightness of the colours (desaturate) making them sometimes more pleasant to be observed.
Due to the fact that grey has a strong colour tinting strenght you should start from the colour hue and adding little by little the grey until you get the desired colour. Once grey is added it is impossible to get back to the initial brightness. The luminosity or darkness of the toned colours will depend on the amount of white or black used to create the grey.
Shades, if we mix black.
In this case we will get darker versions of the colours but the hue itself remains the same. The shade can range from a slightly shade to a dark (almost black) shade.
Due to the fact that black has a strong colour strength you should create shades starting from the colour hue and adding little by little the black until you get the desired colour.
To summarize, the analyse of tints and shades is related to value or luminosity of a colour by constant hue. On the contrary the analyse of tones is related to way the colour purity changes when it is desaturated.
Terms used to describe the Value and the Saturation of hues.
Below a list of the most used terms to define the value and the saturation of hue. Some of these terms can be also found as an addiction to the colour hue itself.
Brightness: it indicates high luminosity or high saturation/purity.
Pure, Bold, Vivid, Rich: all terms indicate high saturation
Paleness, dullness: a measure of desaturation (opposite to brightness). Sometimes we can find the term “pale” together with the name of the hue (for example: pale yellow)
Lightness: similar to the term “brightness”, it describes a colour with a high luminosity but, differently from it, it describes a colour with low saturation.
Darkness: the opposite of lightness, or low luminosity. Usually you can find the term “dark” before the colour hue.
Deep, Royal: used to describe the darkness and/or high saturation of a hue; unrelated to colour depth.
Pastel: used to describe colours with high luminosity and low saturation. The term pastel is usually found together with the colour name (for example pastel blue, pastel red, etc.…).
Neon: bright as the bright glow of neon lighting.
Fluorescent: very bright, sometimes also highly saturated. Named after the fluorescence effect of pigments and dyes when viewed under UV light.
Tinting (colouring) strength
The tinting strength is the ability of a colour to retain its own hue when mixed with white or another colour. This property depends on three aspects:
the type of pigment
the amount of pigment contained in the paint
the fineness of the pigment contained in the paint.
The tinting (colouring) strength is often an indication of high quality acrylic paints, as the amount of pigments they contain is very high.
Type of pigment
Not all pigments have the same colouring strength. Red pigments, for example, are much stronger than yellow pigments, so you need a larger amount of yellow to obtain an orange colour.
The amount of pigment contained in the paint
The second aspect is the amount of pigment contained in the paint. The greater the quantity, the stronger the colouring strenght. This is also one of the reasons why cheaper acrylic paints sometimes look too transparent or colourless on the paper.
The fineness of the pigment contained in the paint
Finally, the fineness of a pigment plays a role. The finer the pigment, the better the paint can retain its colouring power and be applied richly and vibrant to the paper or any surface.
Colour temperature and colour bias: warm and cold tones
Two other terms that are very important when choosing a particular colour palette are colour temperature and colour bias.
Colour temperature: warm vs cool tones
The first term, colour temperature, is a parameter that determines the way we perceive a colour. In this context, there are warm and cold tones for each colour tone.
The colour temperature also depends on where the colour is located on the colour wheel. Normally, colours in the yellow, orange and red spectrum are considered warm, while colours in the green, blue and violet spectrum are considered cool.
Colour Bias
The second term, colour bias, describes the tendency of one colour towards another and can also be an indication of colour temperature. For example, there are reddish (warm) or greenish (cool) variants of phthalo blue based on the pigments used to create the colour.
To find out the colour bias, one method is to see the tint of the colour (i.e. the colour mixed with white).
Interaction of colour temperature and colour bias
As already written, there is usually a cold and a warm colour tone for each primary colour, which can be explained by the colour distortion:
Yellow can tend towards either green or red. Lemon yellow, for example, is a greenish yellow (cold tone), while primary yellow is more reddish (warm tone)
Red can tend towards either yellow or blue. Red-orange, for example, is a yellowish red (warm tone), while magenta or red-purple tend to be cold tones.
Blue can tend towards either red or green. Ultramarine blue, for example, is a reddish (warm tone), while phthalo blue is more of a greenish blue (cool tone).
This aspect of colour bias is particularly important when thinking of complementary colours: if a colour tends to its complementary and is mixed with it (e.g. a reddish yellow and a greenish blue), you get a muddy green instead of a bright green.
In other words, if you want to obtain vivid colours, it is important to mix colours with the same colour distortion or the same temperature.
This is also one of the reasons why we sometimes get muddy or dull colours when pouring: If you select colours that are complimentary to each other (either due to colour distortion or position on the colour wheel), then neutral colours may emerge during the movement of the canvas due to the resulting mixing process.
Colour mixing models
As explained in my previous post about the different colour mixing models, colours can be additively mixed, that is the way we can reproduced the actual light by adding the numeric representations of the component colours, or subtractively mixed, that is the common way to reproduced the colours of objects through pigments or dyes based paints.
In the subtractive models the single wavelenghts of light are partially absorbed by different overlays and what passes through is the colour we perceive.
The most important additive mixing model is RGB-Model; the most important subtractive mixing models are RYB and CMY(K) (for print).
Colour classification in the colour theorie
Chromatic vs Non-Chromatic vs Achromatic Colours
A first classification has to be done between chromatic, non-chromatic and achromatic colours.
Chromatic colours are colours where a particular hue predominates. They are basically the (pure) colours on the colour wheel, ,i.e. yellow, orange, red, purple, blue-violet (indigo), blue (cyan) and green. Chromatic colours are the ones divided into primary and secondary colours.
Achromatic colours (also called non-colours or neutral colours) are colours that have no hue and are also considered unsaturated, near neutral or neutral. There are two subgroups:
Near-neutral colours include browns, tans, pastels (such as pink) and darker colours. Colours in this group are obtained by mixing pure colours with white, black or grey or by mixing two complementary colours. Sometimes these tints, tones and shades of pure (chromatic) colours such as pink or brown are considered non-chromatic colours.
True neutral colours include black, white and all shades of grey.
Primary Colours
Primary or absolute colours are defined as colours that cannot be obtained from other mixtures.
In the RYB (subtractive) model, the primary or absolute colours are: Red, Yellow, Blue
In the RGB (additive) model the primary or absolute colours are: Red, Green, Blue
In the CMY(K) (subtractive) model the primary or absolute colours are: Cyan, Magenta, Yellow
Secondary Colours
Secondary colours are defined as colours that are obtained by mixing primary colours.
In the RYB (subtractive) model, the secondary colours are: Violet (red+blue), orange (red+yellow) and green (yellow+blue)
In the RGB (additive) model the secondary colours are: Yellow (Red+Green), Purple (Blue+Red) and Cyan (Green+Blue)
In the CMY(K) (subtractive) model the secondary colours are Violet (magenta+cyan), Orange (magenta+yellow) and Green (yellow+cyan)
Tertiary Colours
Tertiary colours are colours obtained by mixing a secondary colour with part of one of the primary colours (yellow-green, red-orange, blue-violet, yellow-orange, blue-green, red-violet).
Due to the fact that tertiary colours result from the mixture of all three primary colours, they usually lose brightness and saturation and are labelled as cloudy colours.
Cloudy colours
Cloudy colours are colours that lie in the black-grey-white range, as they are neutralised either by mixing complementary colours (yellow+violet, red+green, blue+orange) or by mixing two primary colours with black.
In the first case, the cloudy colours are labelled as "variegated cloudy" and tend to be warm tones; in the second case, the cloudy colours are labelled as "black cloudy" and tend to be cold tones.
Composite colours
Composite colours are colours obtained by mixing primary, secondary or tertiary colours in different proportions. Brown is considered a composite colour.
Final Words
That was my brief overview of the main concepts in colour theory. It has taught me that colour is a more complex subject that is sometimes underestimated, and I hope I could give you a little more clarity.
In my next post I will talk about the way we can create our own colour palettes.
Thank you for reading. If you like the post, feel free to leave a like, a comment and don’t forget to follow my blog, my Instagram and share the content on your social media.
Have a creative and colourful day!
Laura
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