Saturday, November 19, 2016

Colour Wheels and Colour Harmony

One of the things I learned at the Urban Sketchers Symposium in Manchester this yearn was colour harmony using colour wheels. I took a workshop with the amazing Jane Blundell. She's a watercolour expert, and she taught us about mixing colours and achieving colour harmony using a limited palette. Most of the class saw us painting colour wheels using just 3 colours. But before that, she gave us a quick run through about some important primary colours:

Quick tips on colour

We've all learned about primary colours when we were little. Red, yellow, blue, when mixed in different degrees, produces all the colours of the rainbow. Red and yellow produces orange, red and blue produces purple, while yellow and blue produce green.

But that is just the beginning.


RGB or RYB?

What about computer colours? Why is it RGB (red, green, blue) and not RYB (red, yellow, blue)? Well, that has to do with how light behaves. Colour observed in paintings and prints are subtractive. That means when you add all the colours together, you get BLACK. This happens for reflected light. So when light is reflected off your paper, the pigments absorb different wavelengths of light and you see the reflected result minus the absorbed wavelength. Light from your computer monitor, on the other hand, is additive. That means when you add red, green, and blue, you get WHITE, just like white light can be split into a rainbow. That happens because your monitor is a light source. It is producing its own light, not simply reflecting light like your paper.

One more tip: Our eyes can see a larger range of colours than can be represented with paints or on your colour monitor. Sometimes it may be hard to choose a colour that represents exactly what we see. But don't sweat it. In painting, all colour is representative. Our eyes are constantly adjusting to the changing conditions based on where we are looking and the lighting around us. There's no "true" colour, because the colour we observe of an object is always different at any point in time. Creating a painting is capturing a representation of a scene, even if we adopt a photorealistic style.


Cool or Warm?

We are more concerned with paint pigments here. Non artists may just think in terms of red, yellow, and blue, orange, green, purple, brown, black, white. But there are an infinite number of varieties of each hue. One of the broad ways of categorizing colour is to describe them in terms of warmth. There are cool blues and warm blues, cool reds and warm reds, cool yellows and warm yellows, cool greens and warm greens. When we choose a palette of 3 primaries for mixing, we may choose all warms, all cools, or a mix. I created these reference cards as part of my Sketchpacker kit, and I bring them along in a namecard holder:

Colour wheels using different sets of 3 primaries

Colour Harmony

In each of the colour wheels, I used only 3 colours to achieve all the rest. To maintain harmony, you would want to use colours that fall within the colour wheel. For example, if I'm using Mixed Primaries 1, I can use Sap Green, because it falls within the range between the Hansa Yellow Medium and Ultramarine Blue, even though I didn't use Sap Green to paint the colour wheel. I might not want to use a very cool green like Pthalo Green straight out of the tube without mixing, because it would stand out like a sore thumb. That's generally speaking, of course. Flowers are examples of things with colours that may be vastly different from their surroundings. But even if their colours don't fit into a particular colour wheel, that doesn't mean colour harmony cannot be achieved.

Observed colour is influenced by 3 things: 1) The object's inherent colour, 2) the colour of the light falling on and bouncing off the object, and 3) the colour of the environment bouncing off the object. For example, a red ball placed next to a blue cube will have a bit of blue spill on the side closest to the cube. A colour such as yellow seen under orange lighting will appear more orange, and that same lighting will make it harder to judge blues. I did a painting once in a pub with orange lighting and thought I coloured the skin tones accurately, but when I got out and into the MRT train, I got a shock of my life. I was painting the Simpsons!

Skin tones painted in orange lighting.
I thought I was painting beige. I was actually painting yellow.

If you are aware of how the colour of the object, lighting, and environment affects a scene, you're in a better position to achieve colour harmony.

Staining? Granulation? Opacity? Saturation/intensity? Tonal value? Fugitive?

Watercolours have other properties such as those mentioned above.
  • Staining - How easily your colours can be lifted off a paper using a clean brush and water. Colours which can't be lifted easily and leave a mark are more staining than those that can be lifted easily. Pigments that are ground more finely tend to be more staining. Staining colours tend to produce darker blacks.
  • Opacity and Transparency - More transparent colours will allow the colours under them to show through more. Opaque colours will cover up what is under them more.
  • Granulation - Some pigments will settle unevenly, giving a rough-looking texture that is desirable for some effects. Some pigments interact chemically to create granulation. The result looks somewhat "stoney".
  • Tonal value - How dark a colour is. in the colour wheels above, you can see that Indigo is much darker than Ultramarine at full saturation.
  • Fugitive colours - Some colours will fade when exposed to light. That is why you are not allowed to use flash photography in art galleries, and why your clothes fade after you dry them in the sun over a long period of time. Some colours fade more easily than others. Those colours are more fugitive.
  • "Hue"s - Some watercolour names have the word "hue" appended at the back. That means that is not the true pigment, but a mix of pigments to approximate the original colour. A Cerulean Hue, for example, does not use true Cerulean pigments. Sometimes this is done because the original pigments are no longer available, or they are banned due to toxicity.
More information about watercolour properties can be found here: http://www.watercolorpaintingandprojects.com/basics/properties.html\


Mixing

You can do a lot with just 3 colours! Here are some examples of the exercises we did during Jane's class.

Warm Primaries: Quinacridone gold, Alizarin crimson, Ultramarine


Cool Primaries: Lemon yellow, Perm rose, Winsor blue


Painting fruits with only cool primaries

Final result

So why not try assembling a small pocket palette of your own using just 3 colours? You can pick from the examples above, or try your own.

If you want to find out more about colour, pigments and watercolour properties, handprint.com is an amazing resource.

Thanks, Jane, for all the tips!

Check out Jane's Ultimate Mixing Selection here: http://www.danielsmith.com/content--id-826

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