Colour Theory

Understanding colour and colour theory is crucial in photography, but this is a vast topic that could easily make up a section of its own. Instead, in this class, Karl introduces you to the concept of colour and provides a basic understanding of colour theory and how you can apply it to enhance your photography.

Here you’ll learn about primary and secondary colours, different colour models, hue, saturation and brightness and also how to control colour (this is also covered in more detail in this class here).

This Photoshop class covers the following:

  • Primary & secondary colours
  • Colour models
  • What is a pixel
  • What is Hue, Saturation and Brightness
  • How to correct colour
  • Bit depth explained
  • Colour profiling

If you have any questions about this class, please post in the comment section below.

Key concepts:

Understanding colour

One of the first things to look at and understand when it comes to colour theory and photography is the colour wheel. This will help you visualise different colours and understand how they interact. You can see each of these colours reflected in the most commonly used colour model — the RGB colour model.

The RGB colour model

The RGB colour model, indicating the different RGB values of primary colours.

What makes up colour

As you probably already know, images are made up of thousands of little squares called pixels. Each of these squares is defined by a colour, brightness and saturation value. By controlling colour, essentially, we’re simply adjusting the colour, brightness and saturation of each of these individual squares.

Illustration of pixels

Every image is made up on thousands of pixels.

How to adjust colour

Using either the RGB, CMYK or Lab colour models, you can quickly and easily adjust the colour of your image. This is something we look at in more detail in this class here.

Changing colour in Photoshop

There are different methods for adjusting colour in Photoshop.


  1. Great presentation – thank you. We will be making subjective decisions based on what we see on the monitor. Do you cover monitor calibration etc somewhere?

    1. Hi Sally, I’m pretty sure monitor calibration is covered somewhere here but not sure which class, it may be in the ‘equipment’ section. The best place to head for calibrators and information is X-rite or Datacolor. Certain monitors such as Eizo colour edge have built in calibrators and take care of it all automatically.

  2. Very nicely done Karl. After watching this training video, I realized how little I knew about Colour theory. I loved the plan view colour wheel and 3D representation of colour space which included the brightness component. I was able to find the same or similar graphic color space representations of the colour wheel on-line. The wheel I found calls out the RGB values (0-255) for each primary and complimentary colour. This is a helpful starting point. I have the colour wheels printed and posted in my office until I have the concepts memorized. Thank you Karl for a rich training experience!

  3. Hey Karl,

    That was one of clearest descriptions and presentation of color theory and it’s relation to photography and photographic editing.

    Thank You!

  4. Hi Karl,

    Greetings for the day!!!

    Wow….. What an excellent presentation on colour model. I am sure this model and the other model of Colour adjustment will benefit all. Once again let me thank you to explain it so minutely and in so easy way.

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