“Yeah! The real primary colours are CMY!”
Also bullshit.
Our RGB primaries are a simplification that comes from availability of pigments. While blue was originally a very rare and valuable pigment made from precious stones, it was still more available than magenta or cyan, which are made synthetically.
All of the following is taking paint mixing into mind.
When looking at a continuous colour wheel:
You can see where each colour sits on the spectrum. When you consider a RBY palette, we are limited to essentially the colours in this triangle:
Mixing a vibrant Purple or Green is often difficult with a basic rby colour palette, and a Magenta or Cyan is impossible. We define a primary colour as “foundational colours that cannot be created by mixing other colours”, which means that CMY are real primaries, right? Well, if we look at the CMy palette:
We DO get a wider range of colours, but you’ll notice that a true purple, green, blue, and red are still outside of our range. You can get a pretty close red with Yellow and Magenta, but it will never be as vibrant as a pure Red pigment. So then Red is a primary?
When painting, you should use the colours that you need for the work, and mix from there. The ‘primary colours’ are a tool to teach students the theory of colour mixing. It is not a perfect guide, but teaching complex colour theory to novice painters is just intimidation. Most people get an intro to art, learn RBY, and then leave art, don’t think about it again until a TikTok titled “school LIED to you” introduced CMY.
EDIT: this is from the perspective of an artist. I am not an expert, and certainly got something wrong in here, but the primary argument has always annoyed me
