Understanding what’s really happening when you mix color

You mix exactly the color you want…and then you need more of it.

Somehow, the second mixture isn’t remotely the same!

This is one of the most common frustrations I see artists have with color mixing. We often approach the palette knowing the basic formulas—red + blue = purple, blue + yellow = green—but there is so much more happening than those simple equations suggest.

For those of you who know me, you know I’m a color junkie—and my favorite color is PURPLE.

So why don’t I just buy a bunch of purple paints, squeeze them straight from the tube, and start painting?

Because there isn’t just one purple.

There are bright purples, muted purples, delicate purples, smoky purples, reddish purples, bluish purples and deep, rich purples. And the pigments you choose to mix together can make an enormous difference.

“Mr. Purple,” watercolor and gouache. Notice the range of purples throughout the flowers, stems and bracts.

Red + Blue Doesn’t Always Equal the Same Purple

Take a look at the color mixing chart below.

Each row begins with a different red and each column uses a different blue. Look at how dramatically the resulting purples change.

For example, mixing an orange-biased red with a violet-biased blue gives you a very different result than mixing a violet-biased red with a green-biased blue.

On paper, both mixtures are simply:

RED + BLUE = PURPLE

But visually, the results can be completely different.

That’s because every tube of paint has its own characteristics. When you begin paying attention to those differences, color mixing becomes much less mysterious.

The Goal Isn’t to Memorize Color Recipes

I don’t want my students to memorize dozens of formulas:

Mix this much red with that much blue and you’ll get this purple.

That might work once. But what happens when you change brands? Or pigments? Or need a slightly more muted version? What happens when the flower you’re painting is just a little more violet than the mixture on your recipe card?

Instead, I want you to understand what your colors are doing and why.

Once you understand that, you can make decisions rather than guesses.

Build Your Own Library of Color Knowledge

One of my favorite ways to learn about color is simply to experiment.

The purple chart above is a perfect example. Rather than trying to create one “perfect purple,” I mixed several reds with several blues and recorded what happened.

Suddenly, I have a visual library.

I can look across the chart and see which combinations create brighter purples, which become muted, which lean toward red and which lean toward blue.

And the exercise teaches me something much more valuable than a single recipe.

It teaches me about the paints on my own palette.

You can do this with greens, oranges, neutrals—or any color family you find yourself using frequently.

What Happens When You Find the Right Color?

Then comes the next challenge.

You finally mix exactly the purple you want…but now you need to make it:

lighter, darker, brighter or more muted—without losing the character of the original color.

This is where understanding your pigments becomes especially valuable.

Instead of randomly adding colors and hoping for the best, you can begin making intentional adjustments. And the more you experiment and record your results, the more predictable your palette becomes.

That doesn’t mean color mixing stops being creative. Quite the opposite.

Understanding your materials gives you more freedom to experiment.

And if you know me, you know I believe that:

Experimentation Sparks Creativity.

Want to Explore Watercolor More Deeply?

If you’d like to develop a better understanding of watercolor—from your paints and materials to mixing color, washes, layering and creating finished paintings—my Wonderful Watercolor course is available as a self-paced class with lifetime access.

You can work through the lessons at your own pace and return to them whenever you need a refresher.

 Explore Wonderful Watercolor 

In the meantime, pull out a few reds and blues from your own palette and make yourself a purple chart.

You might be surprised by just how many purples are hiding inside those tubes.

And who knows? You might become a purple junkie, too.

—Mindy