To get started with this tutorial, open Adobe Illustrator and then create a new canvas. When you do this, create an object that we can use for the gradient. In this example, we’ll create a square, but this will work for any object in Illustrator that will accept a fill.
Next, grab the gradient tool from the tool box and create a gradient fill for your object. You might want to open the gradients palette from the "Windows" menu option. Now, create the gradient by left-clicking and then dragging the cursor across the object.
Now, to add a second gradient to this object, click on "Windows" and then "Appearance" from the "windows" menu.
This palette looks a lot like the "Layers" palette. You can toggle visibility of each appearance add blending options, change order, add effects, and perform other operations just as though these were layers.
Now, click on the "New" icon to make a new appearance. As you see in the above image, now grab a different gradient from the "Gradients" window. You can use any gradient, but for this example, just use a stock gradient to demonstrate.
Now, create this gradient on a new "Appearance" layer. You will be drawing over the top of your original appearance, so if this confuses you, click the "eye"icon to the left of the appearance in the "Appearances" window to make the first appearance invisible.
You now know how to create multiple gradients in one object in Illustrator CS4.
Now, you’re almost done. You can now adjust opacity and effects until you get a look you like. To start, click the down pointer to the left of your appearance. You will now see the "Opacity" link. Click it and then you will gain access to all your special blends for each layer. When you are satisfied, voilà! You see how you can get spectacular effects by using multiple gradients in an Illustrator object.
If you think about the way layers work, you will notice that appearances are almost identical in function. The primary difference is that layers affect your entire canvas while appearances only affect one object (or group of objects) at a time.
Now that you have learned how to create multiple gradients in one object in Illustrator, you can experiment with the different effects you can obtain. Keep in mind that you can add more than two appearances to an object and they do not all have to be gradients.
With this powerful skill at your disposal, you will find that your work can be even more creative than it was before.
Image Credits: Screen shots taken by Bruce Tyson