Place an object in front of a vertical surface and light it from the front to create a classic drop shadow. From the chunky, hard-edged "flat-art" look to gauzy blurs from more-distant light sources, drop shadows add depth or emphasis to the artwork you draw in Adobe Illustrator. To create them, choose processes ranging from Illustrator's live effects to hand-drawn methods.
Drop Shadow Effect
Open the "Effect" menu's topmost "Stylize" submenu and choose "Drop Shadow." The two Stylize submenus control two different sets of effects. The one at the top applies Illustrator effects; the one below applies purely pixel-based options you may recognize from Adobe Photoshop.
Set options in the Drop Shadow dialog box. Note that with the Preview check box inactive, you can't see the results of your settings until you click on the "OK" button to apply the effect.
Activate the "Preview" check box. Your artwork reflects the impact of Drop Shadow settings. The Mode drop-down menu determines how a shadow interacts with any objects behind it on your artboard and located on layers that stack below it in the Adobe Illustrator Layers panel. The Opacity setting makes the shadow see-through or solid. The X Offset and Y Offset fields establish the shadow's horizontal and vertical position relative to the original object.
Click on the "Color" radio button to assign a fill color to the shadow. The swatch next to the control's label opens the Color Picker.
Activate the Darkness radio button to tie shadow color to object color and stroke. Note that Color and Darkness provide mutually exclusive options. Set the Darkness percentage to 0 to make the shadow match the object's outermost color. As the Darkness percentage rises, Illustrator mixes black into the shadow color. On objects with a black fill and no stroke, or any fill color and a black stroke, Darkness produces a black shadow.
Apply a Blur radius to add a variable amount of softening to the outer edges of the shadow. Assign Blur in amounts as small as 0.1 points, or 10 percent of 1/72nd of an inch.
Open the "Object" menu and select "Expand Appearance" to turn the output of the Shadow effect into a directly editable object. This step can give you the option of applying effects directly to a shadow, filling it with gradients or patterns, or changing its size and shape.
Examine expanded shadow objects to see whether your effect settings created regular Adobe Illustrator path objects made up of vector artwork. If you leave the Shadow effect's Blur setting at 0, expanded shadows yield vector art.
Look for anchor points around the perimeter of vector objects expanded from the Shadow effect. On blurred shadows, look for selection rectangles surrounding the converted objects, signalling that the expansion process produced bitmaps.
Adobe Illustrator's Drop Shadow effect applies editable detail to objects and text, invoked from the Effect menu's topmost Stylize submenu. The effect's Mode drop-down menu determines how the shadow interacts with objects layered below it. Opacity makes it see-through or solid. X Offset and Y Offset establish its horizontal and vertical position relative to the original object. Blur applies a variable amount of softening to the outer edges of the shadow. Set Color to specify the shadow's fill, or choose Darkness to ties shadow color to object color and stroke. At zero percent Darkness, the shadow matches the object's outermost color. As Darkness percentage rises, Illustrator mixes black into the shadow color. On objects with a black fill and no stroke, or any fill color and a black stroke, setting Darkness produces a black shadow. Illustrator builds pixel-based shadows if you add blur and creates unblurred shadows from path objects.
Working With Blends
Use Adobe Illustrator's Blend tool to create a sequence of shapes that spans differences in color and form between two objects. To assign a specific anchor point on each object as the origin or destination of a blend, click on the starting anchor point on one object and then on the ending anchor point on the other. If you select both objects first, you make the anchor points easier to locate. You also can click anywhere on each object to blend from positions other than anchor-point locations.
Avoid building blends between two objects of dramatically different shapes unless you want a blend that doesn't look like a shadow or you're aiming for a stylized appearance.
Open the "Object" menu's "Blend" submenu and choose "Make" to select options for how Adobe Illustrator creates your blend. Use a duplicate of your original object as the target of the blend.
Use the Blend Options dialog box to control the basis of the blend, and whether the blend objects align vertically to the artboard or arc along the path that defines the blend. By default, Adobe Illustrator blends smoothly between the colors of the two objects. Unless you activate the Preview check box, you can't see the effects of your blend settings.
Set the Blend effect's "Spacing" drop-down menu to control whether the feature creates a specific number of intermediate objects between the starting and ending points of the blend, or inserts a specific amount of distance between the steps. If you want a color-based transition, leave Spacing set at Smooth Color.
Choose the "Specified Distance" Spacing mode to set the distance between blend objects. Because of the potential impact of this setting, applying it with Preview turned off may produce unexpected results. At low values like the 4-point distance assigned to this blend, the effect can look jagged because you see individual blend steps.
Choose the "Specified Steps" Spacing mode to set the number of blend objects. Like the distance setting, this mode can produce chunky edges around the blend area and benefits from previewing. Low values like the eight-step blend assigned to this artwork may look unrealistic even with closely spaced blend objects.
Choose the "Smooth Color" Spacing mode to produce a color-based blend. If you don't like the appearance of the transition between objects, change the color of the shadow object and watch the blend update automatically.
Select the ending object and click on the unlabeled Foreground Color swatch in the Adobe Illustrator Tools panel to open the Color Picker. Change the fill color of the object to alter the end point of a smooth-color blend.
Click on the "OK" button in the Color Picker to confirm the fill-color change.
As a vector-only alternative, the Blend tool gives you manual control of a sequence of paths that span differences in shape and color between a starting and an ending object. Use the Blend tool to set a specific anchor point on each object as the blend's origin and destination, or simply designate two closed or open paths. The Make Blend command in the Object menu's Blend submenu creates blends in one step. To access the full range of Blend options, double-click on the Blend tool icon in the Tools panel or select "Blend Options" from the Blend submenu. Set spacing options to specify either the number of objects in the blend or the distance between the objects, or let Illustrator build an optimized set of blend colors. Orientation options control whether the blend aligns itself to the document page or follows an arbitrary spine, or path, that connects the start and end objects. Edit the start and end objects, and the blend automatically reflects their changing shapes or colors.
Press "V" to switch to the Adobe Illustrator Selection tool. Click on an object to which you want to add a shadow you create yourself. Press "Ctrl-C" to copy the object to the clipboard and "Ctrl-B" to paste a duplicate directly behind the original. Nudge the duplicate out from behind the original with the arrow keys or set its position numerically in the Transform panel.
Set the color of your duplicate object in the Color Picker. To make the duplicate similar in color to the original, alter its saturation or brightness values in the HSB section of the Color Picker, leaving the hue value untouched. To make the object gray, set saturation to 0 percent and brightness to a value less than 100 percent. To make it black, set brightness to 0 percent.
Click on the "OK" button in the Color Picker to confirm the change of fill color.
Select the shadow object, open the "Effect" menu's "Stylize" submenu and choose "Feather" to apply a live, editable effect that softens the edges of the shadow.
Turn on the "Preview" check box to see the effects of your Feather settings. Apply a radius value greater than 0 and watch the edges of your shadow object display a soft blur.
Select the shadow object, open the "Effect" menu's "Stylize" submenu and choose "Outer Glow" to apply a diffuse, soft edge all around the object beyond its outer perimeter.
Set Outer Glow's parameters to turn it into a shadow instead of the bright halos it produces by default. Change the fill color to match the fill color you applied to the shadow object so the glow looks like an extension of the object itself.
Select the shadow object, open the "Effect" menu's "Blur" submenu and choose "Gaussian Blur" to soften the outer edge of the shadow object within the boundaries of the object itself.
Set Gaussian Blur's radius to determine the apparent distance between the object that casts the shadow and the shadow object. The higher the radius, the softer the object edges and the farther away the light source appears to be.
When you want full manual control of a drop shadow, you can create one yourself out of a duplicate of the object or group that casts it. Select the source of the shadow, press "Ctrl-C" to copy it to the clipboard and then "Ctrl-V" to paste a duplicate directly behind the original selection. Alter the duplicate's position with the Transform palette or nudge it into position with the arrow keys, and adjust fill and stroke colors in the Control, Color or Tools panels. To increase the darkness and reduce the saturation of shadow-object colors, select individual objects and set "B" for brightness and "S" for saturation in the Color Picker dialog box.
Illustrator and Transparency
Open the "Effect" menu and choose "Document Raster Effects Settings." This critical cluster of settings establishes the resolution of effects that create bitmapped objects and determines whether those effects use anti-aliasing to smooth rasterized objects, among other parameters. They also control how smooth your blurs and feathered effects look on paper and in onscreen closeups.
Set up DRES to meet the needs of each individual document. For the purposes of creating shadows, the most important DRES options appear in the Color Model and Resolution sections. Additionally, activate the "Anti-alias" check box to assure that Adobe Illustrator creates smooth transitions at the edges of objects with bitmapped effects.
Set the Color Model to RGB to keep color objects in color in an RGB file. In a CMYK file, CMYK replaces RGB in the Color Model drop-down menu.
Set Resolution to "High" for press-quality effects and to keep onscreen renditions from looking pixelated. Choose "Medium" when file size becomes more important than artwork fidelity and "Screen" for rough drafts. If you need a resolution other than 300, 150 or 72 pixels per inch, choose the "Other" setting and enter the resolution value you want.
Watch your artwork's appearance change when you lower the DRES resolution. Your objects need not be selected for DRES changes to affect them.
Select "Medium" to find a midpoint between high resolution and low fidelity. When you're satisfied with your settings, click on the "OK" button to apply them.
Adobe Illustrator's Document Raster Effects Settings, or DRES, determine the resolution of expanded blurred effects and control whether they use anti-aliasing to smooth rasterized objects, among other parameters. If you apply an effect that relies on blurs and transparency, DRES controls how Illustrator builds the rasterized portion of the effect's output. You can see the impact of DRES on an object with Drop Shadow applied to it if you open the "Effect" menu, access the DRES dialog box, and raise or lower the effect resolution. DRES also affects the appearance of files you save for use in other programs.
Illustrator builds pixel-based effects if you add blur, even as little as 0.1 point.
When you create shadows manually, using duplicated or alternate objects instead of live effects, you can hide shadow objects in the Layers panel or through keyboard commands. When you create shadows using live effects, or alter the appearance of a manually created shadow object through an effect, you must turn off the visibility of the effects in the Adobe Illustrator Appearance panel.
To create a shadow object that's the same size as the original without using the clipboard, apply the Drop Shadow effect with no blur and expand the appearance of the effect.
If you create PDF files from Adobe Illustrator, the compression and resolution settings in the PDF-creation interface can lower the fidelity and resolution of bitmapped effects and objects, even if you choose high-resolution settings in the DRES dialog box.
Once you expand a live effect, you either must reapply it, undo the expansion or lose the effect. For these reasons, consider working on copies of your shadow-casting objects or in duplicate versions of your files.
Information in this article applies to Adobe Illustrator CC 2014, Illustrator CC and Adobe Illustrator CS6. It may differ slightly or significantly with other versions or products.