Colour Bias (Video Tutorial)

This video demonstrates how simply mixing two colours together doesn’t always work out…and why muddy colours are formed.

Hi friends, for this Tutorial Tuesday, we’re going to pick up where I left off in last Tuesday’s Colour Theory video!  Mixing colours with acrylic paint (or any paint for that matter) is a bit more complicated than simply picking a random red and blue and mixing them together, expecting a vibrant purple.

Our paint colours are carrying within them hints of other colours, and understanding how this works, how to determine what those colours are, and how to use them to make the colours you want (and avoid the colours you don’t!) are the keys to truly understanding colour theory, and having control over your paint mixing.

After watching this video, you’ll be able to figure out the colour bias of your own paints, and learn how to accurately predict what will happen when you mix two colours together, without any more ugly surprises! lol !

Colour Theory video if you missed it is here (be sure to watch it before this one!)

I’ve also written an article on hub pages about mixing mud here (it’s specific to watercolour, but the principles are exactly the same for any paint).


Here’s the most important points to take away from this video:


  • Colours have both a general and a specific temperature (eg. reds are considered warm colours, but within red there are cool and warm variations).
  • Colours have a tendancy to want to mix towards one side of their colour range OR the other (eg. a red will either lean towards mixing orange OR purple)
  • The “colour bias” of the colour determines it’s ability to mix a bright colour because IT CONTAINS THE ASSOCIATED PRIMARY COLOUR THAT BELONGS TO THE SECONDARY COLOUR IT HAS A BIAS TOWARDS.  (eg. a red that has a bias towards mixing orange contains a bit of yellow within it)
  • This is known as the Undertone.   A colour has a Masstone (it’s general colour…eg. a red) and an Undertone (a red with a bias towards purple has a cool undertone.  This can also be phrased as a purple undertone, or a blue undertone).
  • When we mix colours, we mix both their masstone AND undertone (they are inseparable).
  • Acrylic paints are SUBTRACTIVE, meaning they get darker when mixed, and when all three primaries are mixed together, we get closer and closer to black.
  • If you mix two colours together and get a muddy, dark grey colour, you’ve mixed the three primaries together.  (eg. a red with an orange colour bias plus a blue with a purple colour bias will make some form of dark muddy purple…the red actually contains some yellow within it from the orange bias, so you’ve mixed red, blue, and a bit of yellow…all three!)
  • Bright mixed colours only contain two primaries (eg. a warm red and a warm yellow make a bright vivid orange…the red contains a bit of yellow and the yellow contains a bit of red…only two primaries are involved (there is no blue anywhere here).
  • Get to know your paints:  know which ones are warm or cool within their masstones!

Thanks so much for watching, I hope this video helps!

-Ashley <3

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