An interesting exercise you can do is to go through your studio and round up all the different reds, blues and yellows you have. Above is a photo of all the different yellows and blues I found.

These are the paints:

Cadmium yellow light

Naples yellow

Cadmium yellow

Yellow ochre

Manganese blue

Cobalt blue

Ultramarine blue

So when someone asks "what colors make green?", you can see why it is a difficult question to answer. Yellow and blue is a broadly correct answer, but that does not tell us what we really want to know. There are so many different types of yellows and blues to choose from.

Each of these colors are positions at different locations on the color wheel. You could say that each of these paints are either warm or cool versions of yellow or blue. But remember, it is much more effective to think about color temperature as a relative term rather than an absolute term. So I do not like to refer to a certain yellow as being either warm or cold. I prefer to think of a yellow as being either warm or cool relative to the other yellows.

When you have a few different yellows and blues, what you can do is rank them in terms of relative color temperature.

In theory, the cooler yellows will have more blue and lean towards green. The warmer yellows will have more red and lean towards orange.

The cooler blues will have more yellow and lean towards green. The warmer blues have more red and lean towards violet.

So if I rank the yellows in terms of color temperature from cool to warm I get - cadmium yellow light, cadmium yellow, naples yellow, yellow ochre.

If I rank all the blues I get - manganese blue, cobalt blue, ultramarine blue.

Once you understand these color biases, then you will have a much easier time mixing vivid secondary colors. You see, to mix a vivid secondary color you need to mix just two primary colors together.

But what happens when you mix a warm yellow with a warm blue? Well, by doing that you are mixing a yellow and a blue which both have a touch of red in them. So you are mixing all three primary colors to some extent. What happens when you mix all three primary colors together? You get mud (when enough of each color is present).