Last year I had the privilege of taking a design course with Brenda Malkinson, an excellent fine artist and educator. If there was anything that Brenda emphasized when she taught about colour, it was that artists should choose a basic palette (red, yellow and blue with the addition of white or black to create a tint or a shade of a colour) and stick to it. No introducing a second red or a third blue after the original primary colour chosen has been used.Because the course focused on fine arts rather than graphic arts or digital design, I struggled a little with how to take paint mixing principles learned in the class and apply them to the digital world of graphic design. Brenda helped me to think about how principles from paint mixing could apply to digital "paint" mixing. Below I'll explain a little of what I learned.
Brenda's class transformed how I think (or should think) about colour. As a graphic designer, I don't think about colour wheels enough. I generally would choose secondary or tertiary colours from an image I'd be using in my project. For example, using Photoshop I would choose a green from an image and then use those exact colour values in my layout, so that the image and layout will match.
Instead, when I started on the educational activity folder seen above, I began with only three primary colours (chosen from the fish image that I collaged onto the front right-hand side of the folder.) I created digital swatches for those three colours. Doing some simple digital colour mixing, I made orange, green and purple. My secondary colours ended up looking like pumpkin, mint and mauve due to the primaries I had chosen. (Your primaries have a huge effect on what your secondaries and tertiaries will look like!) Above, you can see the primary and secondary swatches in the bottom right corner of the image, along with the final printed folder and sliders.
The more complicated step was taking my secondary colours and mixing tertiaries. Every colour used in the whole project (13 sets of 3 sliders, one set for each animal, plus a folder) was mixed from my three primary hues. Below you see the second slider from each of the thirteen sets. There is a definite harmony between the colours because they each have their roots in the same primary colours.

Through Brenda's instruction I got a fresh perspective on how simplifying a colour palette creates unity in a design.