Lighting is an important element of any artistic composition; computer-aided vector illustrations, such as those created in Adobe Illustrator, are no exception. Well-designed lighting effects can add a layer of realism to otherwise flat and boring illustrations that seem to lack life. Create a spotlight effect in your illustrations by using Illustrator's built-in tools to draw realistic lighting.
Creating the Backdrop
Create a new document in Illustrator and use the Rectangle tool to draw a square that fits the full size of the document. Select the Gradient tool and click on the square to apply a black-to-white gradient; adjust the gradient slider so that the white stop rests at the upper-left corner of the square, creating an appearance of light emanating from that corner and dimming as it nears the opposite edge of the composition.
Drawing the Spotlight
Create a new layer to hold the spotlight shape. Use the pen tool to draw a cone shape that extends diagonally from the upper-left corner of the composition toward the lower-right corner. Use the Convert Anchor Point tool to round each corner of the cone so that the cone widens as it nears the bottom of the composition. Set both stops on the gradient slider to white and move them along the slider so that they sit at opposite ends.
Creating the Lighting Effect
Double-click the gradient stop at the lower edge of the slider and set its opacity to 0 percent to create a fading effect. Select the cone shape with the selection tool and copy it. Create a second new layer to keep the shapes separated. Paste a copy of the cone shape directly over the original by clicking the "Edit" menu and then "Paste in Place" or using the keyboard shortcut Ctrl+Shift+V.
Using Blurs and Opacity
Select the copied cone on the new layer and click the "Add New Effect" button in the "Appearance" palette. Navigate to the "Blur" flyout and select "Gaussian Blur." Apply a blur of 4 pixels to the shape then use the "Appearance" palette to set the opacity of the shape to 66 percent. Select the original cone and use the "Appearance" palette to set its opacity to 33 percent. To highlight an object with the spotlight effect, place it on the original background layer so that the spotlight shapes will sit above it.