The color modes: RGB vs. CMYK

- In this movie, we'll discuss the two document color modes that are available to you inside Illustrator, and those are RGB and CMYK. And only one mode can be at work inside any given document. And so you may recall, if you go up to the file menu and choose the New command, that you can see the color mode listed down here in the Advanced section, and that's going to change automatically when you select a profile so if you select a print profile, your color mode is going to change to CMYK, but if you switch to any of the other profiles, web through basic RGB, all four of them are going to switch the color mode to RGB, which is generally the way you're going to want to work, which surprises a lot of folks, but the truth to the matter is that RGB is the more flexible color mode while CMYK is designed specifically for print.

And, so, let's take a look at how they work. Both RGB and CMYK stand for the color primaries so in the case of RGB, we have red, green and blue and these are light, by the way, so light that's being projected by a device or captured by a device. So scanners and cameras are RGB devices, as is your computer screen, your gadgets and devices and anything else that lights up. Now because you're starting with a black screen, once you add light, you're going to start brightening things up and to give you a sense for what this looks like, I'll go up to the Window menu and choose Color in order to bring up the color panel, in my case, there's a check mark in front of color so I don't want to choose the command because that would hide it, and then, once you've brought up your color panel, go ahead and click on this double arrow icon a couple of times to expose your primary sliders.

In my case, red, green and blue. If you don't see the RGB sliders, then you want to click on this fly out menu icon in the upper right corner of the panel and choose RGB. Now, notice that you can change these values from 0, that's the lowest, that basically turns the color off, all the way up to 255, which is the highest setting, and so what that does is it gives you 256 variations. 1 through 255 and then you also have the option of 0.

And so when you crank up the red and green values, and you take the blue value all the way down to its minimum, you end up with yellow. If you crank the green and blue values up to 255, and you take the red value all the way down to 0, then you end up with cyan, and if you take the blue and red values all the way up to 255, and you take that green value down to 0, then you end up with magenta, and I want you to notice here inside the color panel how these sliders update on the fly so you can actually preview the color you're going to get.

If I move this triangle mid-way down the red slider, I can see I'm going to get purple, and I can also by the way, as I modify the red value, I can see the green and blue sliders update on the fly. And so Illustrator's always trying to give you a sense for the color that you're going to get because, obviously, there's all kinds of colors besides red, green, blue, yellow, cyan, and magenta. For example, if I crank all these values up to their maximum, we end up with the brightest color there is, which is white, and if we were to take all these values down to their minimum of 0, then we'd end up with no light, which gives us black.

Alright, now let's take a look at CMYK, which is named for the primaries cyan, magenta, yellow and the key color which is black. And as opposed to light, these are inks, and so unlike a screen, where you start with blackness and then you brighten things up, where print is concerned, you start with a bright white page and then you darken things by adding ink to it, which is why when you start mixing the primaries, you end up with darker colors. And so what I'll do is I'll go ahead and click on this fly out menu icon again and switch to CMYK so we can see those CMYK sliders and I'm going to go ahead and crank cyan and magenta up to their maximums of 100% and I'm going to take the yellow and black values down to their minimums of 0% and so as you can see here, when you maximize the cyan and magenta values, and you take out yellow and black, you end up with blue.

If you crank up the magenta and yellow values, and then you take the cyan and black values down to 0, you end up with red, so who knew that red is actually made in part with yellow? And then, if you crank the yellow and cyan values up to their maximum, not surprisingly, you end up with green, but notice that it's not nearly as bright as the RGB green so we're ending up with more muted colors over here. I'm not showing what happens when you add black, and that's because black is a darkening agent, as you can see, so in our case, we're ending up with the darker version of green.

So the big question is, "When should you choose which color mode?" Well, you want to use the RGB mode any time you think your document might be viewed on screen so if you're going to the web or you're creating a .PDF file or an e-book, you want RGB. If you're creating something for a device or an app, then you want RGB. Video is RGB. Presentations such as PowerPoint or KeyNote graphics, those should be RGB documents. If you're creating something for a kiosk or any other screen, you want RGB, and then here's the ringer.

If you're doing personal printing, that is, you're printing to a device at your home or office, and it's an inkjet device, then you should definitely go with RGB and I know that sounds crazy, but here's the thing: inkjet printers have more than CMY and K. They tend to have as many as eight inks, and as a result, they can print way more colors than you can get with conventional CMYK, and they're actually expecting RGB documents, and they'll do a much better job of printing RGB documents and matching the colors than they will with CMYK.

The function of CMYK, by contrast, is very limited. You want to use CMYK when you're creating a document for pre-press. That is, to say, you're going to ultimately be taking the document to a professional print house for commercial reproduction so if you're creating a conventional book or a magazine, then CMYK is the way to go. That's really it, by the way. The only other time you'd use CMYK is because you're doing personal printing to a toner-based CMYK laser printer so in other words, your laser printer only has cyan, magenta, yellow and black toner, and in that case, then CMYK is going to give you a better sense for how your document will look, but even then, you may want to use RGB instead because the printer driver is going to make the conversion to CMYK for you, but your colors are going to diminish.

So take a look at this rainbow over here on the right hand side. Currently, we're working inside of a RGB document and you can see up here in the title tab. There it is right there, RGB. But notice if I go up to the file menu, choose document color, and convert this document to CMYK, which you can do anytime you like, watch what happens to this rainbow right there. It diminishes like crazy. We just lose all kinds of colors. Also notice what happened, I'll go ahead and press CTRL + Z or CMD +Z on a Mac to undo that change, Notice what happens to the RGB green and magenta.

They end up looking like this, and so CMYK is fairly notorious for dropping out bright greens, bright blues and bright purples. You really lose them like crazy so, in other words, unless you absolutely have to work in CMYK, then you should be working with RGB. And that's how the the two color modes work, RGB and CMYK, here inside Illustrator.