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Opacity vs. Fill

Last updated Mar 14, 2003.

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When you have a layer selected, you'll notice that you have two sliders available for your use at the top of the Layers palette. One, which you're probably familiar with, is Opacity and the other, which you might not be familiar with, is Fill. While opacity adjusts how opaque a layer—and all of its contents—are, Fill adjusts just the opacity of filled shapes in the layer. The minor—but important—difference between the two is while layer effects are effected by layer opacity, fill doesn't effect them at all. This feature is tremendously useful in many respects. The following steps will demonstrate this feature so you can have a better understanding of how it works:

  1. In Photoshop, press Cmd + N (Mac) or Crtl + N (Windows) to open the New document window. From the Preset pull-down menu, choose 640 x 480. This auto-fill the new document settings with one that is 640 x 480, RGB, and at 72 dpi. Click OK.
  2. Create a new layer.
  3. Select the Rectangular Marquee tool and draw a rectangle. Choose a foreground color (in this example I chose red) and fill the rectangle with that color. An easy way to do this is to press the keyboard shortcut Option + delete (Mac) or Alt + backspace (Windows). This will fill your selected rectangle with the foreground color that you've chosen.
Figure 1

Figure 1 Rectangle With Fill

  1. Deselect your selection by pressing Cmd + D (Mac) or Ctrl + D (Windows).
  2. Add a Drop Shadow layer style to the layer you just drew your rectangle in. In the Layer Style dialog box, leave all the Drop Shadow settings at their defaults and click OK.

This will add a drop shadow to the rectangle shape in your image. So far, so good.

  1. Lower the Opacity of Layer 1 to 50%.
Figure 2

Figure 2 Changing Layer Opacity

  1. Duplicate Layer 1 by dragging the layer to the Create a New Layer icon at the bottom of the layers palette. This duplicate layer will automatically be titled Layer 1 copy.
  2. Select the Move tool and while holding down the Shift key, press the Down Arrow button on your keyboard about 10 times so that the duplicated rectangle is beneath the original rectangle in the image.
Figure 3

Figure 3 Duplicating the Rectangle

  1. Select the Background layer and create a new layer. This new layer will be created beneath the other two layers in this document that you created previously.
  2. Select a new foreground color (in this example, I chose green) and—using your rectangular marquee tool—draw another rectangle behind both red rectangles in the image. Once you've drawn this new rectangle, fill it with your foreground color.
Figure 4

Figure 4 Showing off the Transparency

As you can see, because both red rectangles are 50% transparent, you can see through them to the green rectangle in the background. At this point both rectangles look the same.

  1. Deselect your selection.
  2. Select Layer 1 copy in the layers palette.
  3. At the top of the layers palette, drag the Opacity slider to 100%, and drag the Fill slider down to 50%.
Figure 5

Figure 5 Changing the Layers Fill %

As you drag that fill slider down, you should immediate notice the major difference between opacity and fill.

Figure 6

Figure 6 Opacity vs. Fill

The rectangle at the top has 50% opacity and 100% fill while the rectangle at the bottom has 100% opacity and 50% fill. While opacity adjusts the opacity for everything on a particular layer, fill only adjusts the opacity of fills while leaving layer styles untouched. In a real-world environment, I find myself using this feature—to accomplish one particular goal or another—in nearly every project. As you can see, Fill offers you a great way of altering the opacity of a layer without effecting layer styles that you've added.