A knockout effect allows you to place a solid layer of color over a photo or image, and then punch out some of that solid layer to reveal the image behind it. You can do this with text or shapes both in Photoshop and Illustrator, but the process is slightly different for each program.
To achieve a knockout effect in Photoshop or Illustrator, the first thing you’ll want to do is open up your image. In this example, we’ll use a rectangle shape over the image, and knock text out of that shape.
Step 1: First, draw your rectangle using the shape tool. You can either select the shape tool from the tools menu, or you can use the keyboard shortcut U. When you draw your rectangle, you can either choose free form and drag the rectangle across the screen to create the shape you want, or you can click anywhere on the image to enter the dimensions of your rectangle in pixels.
Step 2: Next you’ll want to type in your text on a separate layer in Photoshop or on the same layer in Illustrator. If you prefer to use a shape or icon for your knockout, you can place that shape where you would have placed the text.
If you’re using Photoshop, move onto this step. If not, skip down.
Step 3: Right click your text layer and select Blending Options. On the tab that opens up, look for the Knockout setting under Advanced Blending. You can choose between a Shallow or Deep effect from a drop-down menu.
When you first make your selection, you won’t see anything happen on your image until you drag the Opacity bar above the setting. Here you have complete control over how much of that original text will be visible. The color of your text will make a difference here unless you choose for an opacity of 0 percent. If you have a particularly busy photo, however, you probably won’t want to choose a very low opacity in order to keep the text legible. (If you want to preview the changes before accepting the changes, make sure you have the preview option checked.)
You can then drag and adjust the rectangle and text layers to place them exactly where you want them on your image.
In Illustrator you follow Steps 1 and 2 outlined above, but in order to achieve the knockout effect, you’re going to have to use a different tool.
Step 3: Once you’ve inserted your text, in the menu, while still on your text layer, go to Type > Create outlines or you can use the keyboard shortcut Shift + Cmd/Ctrl + O. This will convert your text into shapes rather than editable text. Make sure that your text is on top of the shape and not behind it. (This step will not be necessary if you used a shape in step 2 instead of text.)
Step 4 (Optional): If you want to be able to control the opacity as is possible in Photoshop, make a copy of the text layer with the keyboard shortcut Cmd/Ctrl + C. You won’t need to do anything with it until after Step 6.
Step 5: Select both your shape and text and go to your Pathfinder tools. If it isn’t already open, you can open it by going to Window > Pathfinder or by using the keyboard shortcut Shift + Cmd/Ctrl + F9.
Step 6: In the pathfinder tool, select the Minus the Front option in under Shape Modes. This will remove the text from your shape.
Step 7 (Optional): If you want to control the opacity of your knockout effect hit Shift + Cmd/Ctrl + V to paste your text back in the exact place you copied it from. (Make sure to do this before you move any of your layers.) You can then adjust the opacity of that layer by going to the Transparency panel, which you can open by going to Window > Transparency. Adjust the opacity slider until you have the exact shade you want.
With an opacity of around 20 percent, this is what the final product looks like:
What kinds of uses can you think of for this technique? Let us know in the comments.