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The "Color Modes" Lesson is part of the full, Design for Developers course featured in this preview video. Here's what you'd learn in this lesson:

Sarah explains additive and subtractive color mixing modes, and how it affects the end color product.


Transcript from the "Color Modes" Lesson

>> Sarah Drasner: Okay, so for color, let's talk about color modes first. And we're also just gonna talk about color mixing and color in general. Because color mixing and color modes are kind of interrelated. So, the way that you might know color in terms of like the way that it usually taught in schools is like red, yellow, blue are primary colors.

What if I told you that's not true? [LAUGH] What if I told you all of that is a lie? And that it really actually matters what kind of color mixing you're using. So there's different types of color mixing. One of them is called additive color mixing. And one of them is called subtractive color mixing.

So when we talk about red, yellow, blue, well, we're actually really talking about cyan, magenta, and yellow, plus black. And that is a subtractive process. And the reason why it's a subtractive process is you're basically subtracting light. And it's a little bit more complicated than that, but that's kind of a base thing to understand.

When we talk about additive color mixing, additive color mixing is actually red, green and blue to make all of the colors. So here's additive and subtractive color mixing. When you're working on the computer, you're not working with red, yellow and blue, you're working with red, green and blue to make all of the colors.

And all of the colors blended together lead to white, instead of lead to a darker color. Sometimes we do things in Photoshop, or Illustrator, or Sketch, those kind of documents, they know that your brains will think you're using subtractive color processes. So it will kind of compensate for that, and make it seem like it goes in the other direction.

But really, it works like this. So if I took a bunch of flashlights, if I had a flashlight that was red, a flashlight that was green, and a flashlight that was blue, and they all lined up, you get a white flashlight in the middle. Or if I took red and green flashlights, and I shown them each other at the wall, it would turn into a yellow light.

Unlike subtractive color mixing, and we have C, M, Y. And really when we mix up C, M, Y, we get some sort of deep brown, which is why, in printing processes, we actually add K, which is black. That gives us a richer black than we could get by mixing all those pigments.

And it's called subtractive color mixing because basically you have a vehicle. So if you're painting, you have a vehicle of oil or gum Arabic if they're using water color. Or Acrylic 65 if you're using acrylic paint. And you have that vehicle. And then inside that you have all these kind of particles and pieces of pigments.

And those pigments will be those pieces of color. So if I'm using red, I might use cadmium rock. Break up the cadmium rock until it has all of these little pieces. And then maybe add some alizarin crimson, some different types of rocks until we're mixing together and making new colors.

So, we're actually subtracting light in that instance. And that's why it's called subtractive color mixing. The reason why I'm telling you all of this is not because you need to remember it necessarily. But that's why when you're working with Photoshop or Illustrator, or anything like that and it asks you the color mode that you're working in.

You're always working in a color mode whether or not you're deciding to, it always has a defined preset for a color mode. RGB is for the screen, and CMYK is for printing.

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