You can find patterns in your Swatches window.
Related: How to Vectorize an Image in Adobe Illustrator These patterns will also give you an idea about how to use your own patterns once you've created them. Illustrator comes with several patterns built right into it. In addition to being useful in their own right, they're also a good way to see how patterns work. Using the Default Patterns in Adobe Illustrator Here's how to use Illustrator's pattern tools, and how to create and edit your own patterns. Patterns are great for backgrounds, textures, and more. You can even use a part of an existing vector graphic, and turn that into a pattern as well. You can make something simple, like a pattern of dots, or do something more complex. See the image above with the same star filled with a color gradient.Create a pattern in Adobe Illustrator, and you can quickly apply it to shapes, strokes, and even text.
I chose to use a one color object for the sake of keeping this tutorial simple, but you can apply the same technique to a full color object for different results. Plus, it adds a little more flexibility for later editing. Why would you want to do it in Illustrator? Because many sign shops and screen printers require everything to be a vector shape depending on their production methods. You have your halftone-dot effect, and it’s a fully-editable vector object in Illustrator. Because the star is a compound path, all the dots will be colorized. Now select the star again and add a color to it as you would any other object. You should be left with nothing but the dots now.
Now that all the white areas are selected (including the white bounding box around the star, hit Delete. Go to Select>Same>Fill Color in the menu. Use your Direct Select tool (the white arrow) to select any white are in the newly created halftone dot area. See the image at the right for an example of what I’m talking about. If you want it to be transparent, you have just a bit more work to do. You’ll notice that the inside of the star remains white. But draw a box, fill it with color and send it to the back by hitting Command-Shift-[. Step 4: If the star is on a white background, everything will appear to be perfect. You can select each dot individually if you choose because they’re all vector shapes (see step 3 in the image above). Now select Object>Live Trace>Make and Expand from the menu. Step 3: With the star still selected, go to Object>Expand Appearance in the menu. We need to convert the raster image to vector. The darkest areas of the star have the largest dots, and the lightest areas have smaller dots. The star is now converted to a raster image. Go ahead and leave the screen angles at the default setting. This will determine the size of the largest dot in the effect. The color halftone dialog box will open where you can enter some numbers to adjust the appearance of the effect. Step 2: Select the object and select Effect>Pixelate>Color Halftone… from the menu. To achieve the mixed-size dots, you’ll want to use a gradient, and to make it easy later, you should probably start with a simple black color. Step 1: Create a shape in Illustrator that you wish to convert into the halftone-dot effect.
I’m happy to report that there is, and I’ve put together a tutorial to show you how. Recently, a reader left a comment on the post asking if there was a way to achieve the same effect in Illustrator. A while back I posted a link that would show you how to create an interesting halftone-dot effect in Photoshop.