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Any grayscale PSD (Adobe Photoshop document) can be used as a custom texture in Adobe Illustrator. In this screen cast, learn how to create a Photoshop texture without ever leaving Illustrator, then use it with the Texturizer effect. Illustrator has tons of built-in textures under the Effects menu that you can apply to any object. But why use an out-of-the-box texture when you can easily create your own?