Fine Selections Using Photoshop's Extract Filter

(Intermediate level)

Ever try to select someone (or something) with fine wispy hair? Trying to do that with the lasso, pen tool or even the quick mask can be full of frustration. Adobe Photoshop CS2's Extract Filter comes to the rescue.

The Extract filter dialog box provides an elegant way to isolate a foreground object or objects and remove the background on a layer. Even objects with wispy, intricate, or undefinable edges may be clipped from their backgrounds with a minimum of effort. When you extract the object, Photoshop erases its background to transparency. Pixels on the edge of the object lose their colour components derived from the background, so they can blend with a new background without producing a halo effect.

Original	Using the lasso and magic wand	Using the extraction filter method

If you would like to follow along with this tutorial you can download the picture of Della the Afghan Hound by right clicking on the link dog-bride.tif and choosing Save Target As from the resulting context menu.

Launch Photoshop and Open dog-bride.tif or a picture of your choice.

Step 1: Duplicate the Background Layer

As the Extraction Filter is destructive, meaning that it permanently alters the image, it is best to work on a copy of the image layer. This way if something goes wrong you can just duplicate your starting layer again and start fresh. Copy the background layer by dragging the the dog bride layer over the new layer button at the bottom of the layers palette and releasing the mouse or by choosing duplicate layer from the palette options menu.

Step 2: The Extraction Filter

With Dog-Bride copy layer selected Choose Filter > Extract. The Extract Filter opens up in its own window with a selection of tools on the left hand side and a set of options down the right.

Step 3: Defining the selection border

When using the extraction filter we first need to define the border of our selection. Start by drawing a marquee around the dog's head with the zoom tool to get a closer view.

Choose the marker tool from the tools at the left side of the extraction filter window. Set the brush size in the tool options section. A general rule of thumb is that if the line is clearly defined go with a fairly small brush and use a slightly bigger brush for softer or wispy areas. In this image I used a 2 pixel brush for the clear edges and 4 or 6 pixels for softer or blurry areas. Tip: you can change the size of your brush on the fly by clicking the right and left brackets on your keyboard. If there is a clear border you can also select the smart highlighting which will help you hug the border as you draw. The default brush colour is green so if you were trying to extract a tree or green plant you might want to choose a more visible colour to work with. The green shows up well on the dog so we will leave it colour as it is for this project.

You want to draw so that the middle of the marker line is over the actual edge of the selection. When you encounter a wispy area draw in the wispy bits even if that means covering a chunk of background.

Use the eraser tool to remove any mistakes. Tip: Hold down the Alt (win) or Opt (mac) while drawing with the marker will switch to the eraser tool.

Step 3: Filling the Selection

Once you are happy with your selection border, Choose the paintbucket tool and fill the area. Make sure there are no areas that are not filled. Sometimes if the edge is complex the marker with block the paintbucket from filling properly. If that happens used the eraser and marker to clean up that area.

Step 4: Previewing your selection

Now we get to see how good a job we did - the extraction process seldom works so perfectly the first time that you don't have to tweak a little. The preview option will allow us to see how the selection looks before committing to it and we can go back and refine any areas that look a bit rough.

Click the Preview button near the top of the Extract window. For this particular image - I would choose a white matte from the preview options near the bottom. This will do the best job of showing up the defective areas.

In the image above you can see that while a most of hair looks good there a few spots on the left side of the dogs head and neck that need a bit of work as well as the dogs tail.

Step 5: Refining the Selection

To refine our selection we need to switch back into editing mode and we do that by selecting Original from the Show drop down menu in the Preview section. Make sure Show Highlighting is checked. Use the eraser tool and marker to adjust any of the wonky areas. Then use the paintbucket to again fill the selection. Once the selection has been filled the Preview button becomes clickable (it is greyed out otherwise) and you can preview your changes again. This process can be repeated as many times as needed.

Tip: You use also the clean up tool and edge touchup tool and work in the non-highlighted extracted image preview.

Once you are happy with your selection click Ok.