The Extract Filter

The Extract Filter is not something someone new to Photoshop should be tackling. It's better to improved techniques with the other methods of selection first, so I've put this method in the Advanced section.

The Extract filter works like a multi-function tool. There are a number of techniques which can be used on hard-edged subjects but the Extract filter comes into its own when delicate subjects like animal fur or hair need to be separated from the background.

• For this photo shop tutorial, open image 06.jpg in the Samples-Various folder.

  Position it so that the cat's tale is at the top of the screen.
  When we extract the cat, the tale is the most difficult, so it helps to have the original open to view for comparison.

• Go to Filter > Extract.
  Tools are on the left, settings on the right.
  Zoom in as usual with Ctrl + Plus / Cmd + Plus.
  Zoom out with the minus sign.
  
  
  

• The Edge Highlighter Tool (B) is selected by default. For wispy bits and delicate edges use the standard brush.
  Enlarge the image and choose a brush size of 20.
  The brush size should be just sufficient to cover the edges and all the fluffy bits.
  Set the Highlight colour to Red to give a good contrast with the background.
  
  

• Work the brush around the edge of the tail.
  Brush size can be changed at any time.
  The image can be moved around the screen with the space bar and the hand.
  
  
• The carpet has a more definite edge and contrast. Smart Highlighting works well here. It works like the Magnetic Lasso and will lay down a highlight line just wide enough to cover the edge.
  Carefully work the brush along the edge of the carpet. Highlight round the carpet and back to the start.

• It's best to work with the image enlarged as much as possible to aid accuracy.
  There is only one undo with the Extract filter with Ctrl + Z / Cmd + Z, but everything can be reset to the beginning; hold Alt and the Cancel button changes to Reset as usual.

• The highlight needs to go round the whole object, although it does not have to cover where the object touches the frame of the image.

• In the Extract filter toolbox, select the Fill Tool (G), the Paint Bucket.
  Click in the centre of the selection to fill in.
  Click on Preview. The background is reduced to transparency but it can be difficult to see the subject in parts.
  Bottom right is a pop-up menu called Display. Clicking on Gray Matte provides a grey background, to make it easier to see the subject.
  Any colour can be chosen under Other.

• A few little parts of background are left and some of the subject has been lost.
  Select the Cleanup Tool (C), which will erase unwanted bits and restore subject matter that has been lost. Brush out any unwanted background.
  The strength of the eraser is controlled by the keyboard numbers: 1 is the weakest at 10%; 9 is 90% and 0 is 100%.

• It can be difficult to see exactly what detail has been lost from a very wispy subject but with the original on the screen, we can check it.
  Still with the Cleanup Tool, hold Alt and brush over the areas where fur detail is lost. Use low keyboard numbers because subtlety is best here.
  So the Cleanup Tool will eraser the image, while the Cleanup Tool with Alt will restore it.
  Work your way round the edge of the carpet.

• The carpet should have a reasonably sharp edge and the Edge Touchup Tool will help. Select it from the toolbox and work it along the carpet edge but not over the fluffy bits.
  
  When finally satisfied, press OK and the background it removed from the original.

• The image is now ready for dragging on to a suitable aerial photograph.

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