Join Mordy Golding for an in-depth discussion in this video Getting to know the color models, part of Illustrator: Coloring Artwork (2011).
Before we get started learning how to actually use color inside of Illustrator, we have to have a discussion about color models, these are also called color modes and we maybe familiar with some basic ones like RGB and CMYK, for example. Now first, let's understand what a color model actually is. Basically a color model is simply a mathematical way that we can describe color. For example, using the RGB color model, we actually mix values of red, green, and blue to achieve any color that we want.
Whereas, in the CMYK color model, we combine values of cyan, magenta, yellow, and black. Now one of the first times that we as Illustrator users need to make a decision about what color model we want to use, is when you first create a new document. For example, if I go to the File menu here and I choose New I'll see that in the New Document dialog box, if I have the Advanced options visible, I can see a set here called Color mode. Now an Illustrator document must be set to either CMYK or RGB, those are the two choices that we have.
Now a lot of people think that just CMYK means print and RGB means web, that's not necessarily the case. The main reasons why Illustrator forces you to choose one of these twos, because it can sometimes be bad if we have a single document that contains both a mixture of colors that are used with CMYK and colors that are used with RGB. Because usually, when I print my document, or I output my document I printing it to a single source, so I might see color shifts that are involved there. If you go back to many years ago, especially before the days of consistent color management, it was difficult for a designer or prepress operator to control the color that they got out of their computers.
So when Illustrator 9 was released, Adobe made it so that each Illustrator document had to be either CMYK or RGB and that's where we have these options here. But I will tell you that there is some value in actually mixing these two color models in a single document. For example, in the world of packaging we may find that some artwork we'll actually be printing using both process colors and also some spot colors. Now those spot colors maybe things like metallic colors or pastel colors or things that are very, very rich, and that can't be actually created or even simulated in the world the CMYK.
If you force the entire document to be CMYK, then you really have no way to proof or even simulate those brighter colors. In fact, we'll learn throughout this title that Illustrator actually does allow you to get into a situation where you can have mixed color models in a single document. The way that you do that is, for example, you might create a CMYK document, but you would actually place an image and that image will be linked, it wouldn't be embedded, but it will be linked and that image that is linked, could be an RGB image. So in essence what I'm getting at here is that when you create a new document, then you choose a color mode be a CMYK or RGB.
It's the artboard itself that's limited to that color model. However, Illustrator still has the ability to link content. Since that content doesn't actually belong to Illustrator, it's actually referencing an external file, that file can actually have a separate color model. There are also additional ways to me to actually create a single document that has colors using different color models inside of it, and again, we'll visit that throughout the title. For now though, note that when you create a new document, you must choose either CMYK or RGB. This is really purely for consistency.
I don't want to get into a situation where I might create some artwork and then experience color shifts later on. Now, since most print artwork actually does print using CMYK, and since most web designs actually do get displayed on monitors which use RGB, we find that general kind of umbrella or this generalization that just says; well basically, if you're doing print design, use CMYK, and if you doing web design, use RGB, but what I want you to remember here is that I'm simply choosing a color model.
Meaning, I want my artboard to use a certain color model here. But don't mistake these Color modes for actual different workflows like print and web. In fact, don't assume that Illustrator only supports CMYK or RGB either. Once I create my document, and I'm going to create this document right here using the CMYK color model, I'll find that when it comes to actually defining colors inside of Illustrator, I have more color models at my disposal. I'll open up my Swatches panel right here, and let's say I just want to define a new swatch. So I'm going to go to this button down here at the bottom, choose to create a New Swatch, and you'll notice that where it says Color mode; that I want to create a color here I can choose between these different color models.
I've Grayscale, RGB, HSB, CMYK, Lab, and Web Safe RGB. Now again, these aren't color modes that my document is in, these are color modes that I can apply to the colors that I define here as swatches inside of Illustrator. Now, Grayscale is simply how much the different values, there is actually 256 levels of gray that exist in a single channel, but we usually measure Grayscale as numbers from 0 to a 100. Zero being white, 100 being black, and any number in-between as different shades of gray.
Now RGB, HSB, and Web Safe RGB are very much the same. RGB of course, standing for a red, green, and blue, but HSB is just a different way to interpret that. You know the brain doesn't really focus on red, green, and blue in a way that we can actually kind of come up with colors. HSB would stands for a hue, saturation, and brightness is a far more intuitive way of understanding how color works, more importantly, how we can define color. A little bit later inside this chapter, we'll actually go into detail about exactly how HSB works, and more importantly, how it's going to help us throughout the rest of this title.
Now Web Safe RGB is simply a subset of RGB colors, it's actually 216 specific colors that are consistent across both Mac and Windows platforms at the system level. The thought-process behind Web safe RGB was simply a way that we can guarantee a lowest common denominator, or a set of colors that will always be found on any computer system. In reality, the whole concept of Web Safe RGB colors doesn't really apply much today. And that's because nowadays most people have monitors that can display many, many different colors.
Now it's important to realize that RGB, HSB, CMYK, and Web Safe RGB, are what we refer to as Device Dependent Color models. That means that the color that we actually get depends on the device that you're viewing that color on. For example, it's possible for me to create a color on my computer screen using very specific CMYK values. I can then go over to my friend's computer type in those exact same CMYK values, but the color that I see on the screen won't be the same.
That could be, because the manufacturer of the actual monitor itself is different, and each manufacturer may build their monitors in the way that produce a different type of color. The same thing applies to printers. I can take a single file that has CMYK colors and print it to one printer and get one set of results. And I can print that same file to a different printer and get different results. It's the same CMYK values that are being used to actually print those colors, but I actually see two different results. That's because what I see, what I perceive that called to be, depends on the device that's actually creating that color.
In these cases it's the printers. Now there is one other color model here that's listed inside of this dialog box which is called Lab. Lab which is broken down to three channels L stands for lightness, and then we have A, and B channels. A contains reds and greens and B contains blues and yellows. It's a different kind of color model completely. In fact, Lab is referred to as a device independent color model. Scientists who actually developed Lab is to define color based on how humans actually perceive that color.
So in reality, Lab is a far more accurate way to describe what an exact color is. However, because our computer monitors and our printers, and devices that we use all are RGB and CMYK, all color must eventually be translated to those different color models. Now why are you even talking about Lab here at all? The answer is that later on in this title we may find out that Lab can help us in getting more accurate color on our devices. However, you would ever actually use Lab to define a swatch inside of Illustrator.
In fact, for the most part inside of Illustrator, you'll probably define colors using CMYK, RGB, or Web Safe RGB. And as we're soon going to see later on in this chapter, you may find that working inside the HSB color model, is far more intuitive for defining colors and you may define your swatches using that. So that's a brief overview of the color models that are supported inside of the Illustrator workflow. Remember, that each document can be set to either CMYK or RGB, and when I define my swatches, I can use any of these color models that you see here as well.
- Getting to know the color models
- Defining and using process and spot colors
- Creating swatches and groups
- Managing a color library
- Getting inspiration from Adobe Kuler
- Setting limits on the Color Guide
- Protecting black, white, and grey
- Making global color adjustments
- Reducing colors
- Converting to grayscale
- Proofing colors
- Previewing color separations