Texture is another from that is important to show in designs. 

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There is always texture in design.  Even if the appearance of the design seems flat and non-existent, there is still texture present.  Texture can be achieved in a variety of ways.  It can be done by using a pattern, or done by using a gradient mesh to enhance a shadow of an element on your page.  Either way, a texture is present.  It can by shiny, smooth, or flat and rough.  Through my experience with catalog design and email marketing, textures prove helpful to move your eye around the page.  Using a texture can also create shape, line, rhythm, movement, and form in your design.  Using texture can enhance the visual quality of your message that you are communicating. ("Color Theory for Designers, Part 1: The Meaning of Color”)