A filter is a special kind of tool designed to take an input layer or
    image, apply a mathematical algorithm to it, and return the input layer or
    image in a modified format. GIMP
    uses filters to achieve a variety of effects and those effects are
    discussed here.
  
        
          The filters are divided into several categories:
          
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                Secção 3, “Blur Filters”
               
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                Secção 4, “Enhance Filters”
               
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                Secção 5, “Distort Filters”
               
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                Secção 6, “Light and Shadow Filters”
               
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                Secção 7, “Noise Filters”
               
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                Secção 8, “Edge-Detect Filters”
               
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                Secção 9, “Generic Filters”
               
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                Secção 10, “Combine Filters”
               
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                Secção 11, “Artistic Filters”
               
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                Secção 12, “Decor Filters”
               
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                Secção 13, “Map Filters”
               
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                Secção 14, “Rendering Filters”
               
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                Secção 15, “Web Filters”
               
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                Secção 16, “Animation Filters”