Illustrator - Color - Part 1

The first part of this tutorial deals with color and is not intended solely for Illustrator. The information here is good to know (even if sounds a bit boring) no matter what application you use to create your art. The second part deals with setting up colors and swatches for Illustrator. We won’t go into what exactly color is. That is a more complicated matter than it sounds. Everybody knows what colors are… right? Blue like the sky, green like the grass and so on. The way your eyes perceive color is another matter altogether. You’ll come across a few terms when dealing with colors in applications like Illustrator or Photoshop…and many many others. Terms like “hues” or “tints” or “blends” and even menacing sounding acronyms like CMYK or RGB.

A very quick introduction to color theory would be this:

There are 3 primary colors – red, blue and yellow. If you mix those 2 at a time you get secondary colors – green, orange and purple. If you mix a primary with a secondary you get a tertiary color. Green and Blue for instance give you Cyan. So far it’s pretty straightforward. From now on it gets more complex. Colors can be cool: blues and greens and violets - and warm: yellows, reds, oranges. If a color makes you think about summer – it’s warm – if it makes you think about winter or frostbite – it’s cool. Other colors are neutral – they don’t make you think in terms of temperature. Like browns and grays.

Tints are colors that have white mixed in them. As soon as you add white to a color you made a tint. Shades are just like the name says – shadows – and it takes black to make one. Colors are furthermore separated into other classes: analogous colors (colors that are close to each other on the spectrum, for instance greens and yellows) and complementary colors – colors that are exact opposites on a colorwheel – like reds and cyans or blues and yellows. Out of these combinations come color schemes.

But enough about color theory. The above are very simplistic explanations to a very complex subject. There are a lot more in-depth tutorials that cover color theory; if you’re really into it you’ll find them. Take a look at my picture.. it shows what I tried to explain so far:

Color wheel

You do need to understand the difference between RGB and CMYK. These being the major working color modes of Illustrator (and any other self-respecting application).

RGB means RedGreenBlue – and it’s what monitors (and TVs) use to output color.

CMYK means CyanMagentaYellowBlacK They used “K” for black because “B” was already taken by “Blue.” CMYK colors are used by printing machines (the big ones) and are present in any printed paper you ever held. Why are RGB colors used by monitors and CMYK by printers? It’s easy enough – a monitor is a device that emits light. As such, red green and blue phosphors – the “lights” in the monitor are combined to make all the other colors. In a monitor’s case red and green and blue are added in various “quantities” to make a certain color. It’s easy to do so. It’s not so easy in the case of paper however. Paper is not emitting light – it’s not plugged in. Paper is absorbing light. Or more to the point light is “shone” on the paper and bounces back to the eye. So while a monitor’s color space is additive (because one color is added to another to make a third) a printer’s color space is subtractive. You obtain blue for instance by subtracting cyan from magenta and red by subtracting yellow from magenta. This is why paper needs CMYK input. While in theory the same colors can be obtained in both working modes RGB and CMYK, their spectrums (the total number of colors) differ. Which is to say that CMYK “sees” more colors in some areas than RGB and less in others. The same is valid for RGB. On top of it all – the human eye sees a whole lot more colors than both working modes – about 3 times more colors. So how exactly do you make peace between RGB and CMYK? Illustrator (and some other apps) offers another choice – spot colors. Spot colors are colors that are not CMYK process colors. Like Pantone. These are special colors that printers’ people can buy in cans and use for an exact match. The reason many digital creators use Pantone colors is that the spectrum is slightly larger than both RGB and CMYK spectrums. It encompasses both. However, Pantone colors are more expensive than CMYK process colors (simply because instead of buying 4 cans of paint – cyan, magenta yellow and black, you have to buy additional cans – with the Pantone colors). If price is a big issue when creating a piece of digital art try to steer away from Pantone and stick to good old CMYK.

Color spectrum

You know how astronauts going out to space say there’s no picture that can describe the actual landscape they see? Or proud Irish saying their impossibly green grass has hues no photograph can do justice to?

They’re right!

In any case it is important to understand that CMYK colors will not show as they really are on your monitor because the monitor can only use RGB to output them. When working in Illustrator I personally prefer to work in CMYK because you never know when you might need to print it and if you try to convert from RGB to CMYK some colors may alter.

Other terms you may come across are Halftone and Duotone. They mean very different things. Halftone is the process used by printers to vary the apparent intensity of color on paper. In order to understand about this you need to understand how offset printing works. We already spoke about CMYK colors. Well – any piece of digital art you produce is separated into 4 parts. One for every color. At the printer house they call those “plates” because each of the 4 colors gets a plate (aluminum or plastic or something else) that is etched with acid or any other method so that your image (just the Cyan part for instance) is “carved” onto the plate. The process is then repeated for magenta, yellow and black. The plates are then smeared with paint according to their color – cyan paint for the cyan plate and so on. The paper on which your drawing will finally reside will pass over each of the plates and from each will get an amount of paint. When combined, the 4 colors will trick your eye into believing there are many more. Which gets us back to halftones. Halftoning means that tiny beads of paint are put on the paper on a grid. The “dots” can be smaller or larger – the grid can also vary in angle. The smaller the dots of paint and the larger the grid – the lighter the color will seem to be in intensity. The larger the dots and the higher the apparent intensity. Grids are arranged differently for all 4 colors so that when combined they overlap and make a pattern the eye perceives as your image. When you count how many halftone lines there are in an inch on the paper you get the LPI measure. LPI means lines per inch – or screen lines per inch. LPI is the term for image resolution when speaking about print stuff – just like PPI (pixels per inch) is the measure for digital images. As an example – regular newspapers use a resolution of 85 LPI. Which means you can see the dots patterns (halftones) with the naked eye – if you look closely you’ll see them). Platesetters can print up to 200 LPI which means the resolution is so much higher.

Duotone on the other hand is a name the press people gave to multitone printing. Duotone means 2 inks (or 3 in which case it’s “tritone” or 4 when it’s “quadtone”) will be used to output the image. Duotone images require spot colors to be used – Pantone usually. How does it work? - A monotone image (1 ink) with a dark color is tinted (overprinted) with a lighter one to tone it … and that’s it.

Ok, we should have enough info to get to the second part of the tutorial – color management in Illustrator space.