4.10. Separating an Object From Its Background

图 3.39. Object with Background

Object with Background

Sometimes you need to separate the subject of an image from its background. You may want to have the subject on a flat color, or keep the background transparent so you can use it on an existing background, or any other thing you have in mind. To do this, you must first use GIMP's selection tools to draw a selection around your subject. This is not an easy task, and selecting the correct tool is crucial. You have several tools to accomplish this:

4.10.1. Once you have selected your subject

Once you have selected your subject successfully, use SelectInvert. Now, instead of the subject, the background is selected. What you do now depends on what you intended to do with the background:

  • To fill the background with a single color:

    Click the foreground color swatch (the top left of the two overlapping colored rectangles) in the toolbox and select the desired color. Next,use 第 3.4 节 “油漆桶填充” to replace the background with your chosen color.

    图 3.43. Result of Adding a Plain Color Background

    Result of Adding a Plain Color Background

  • To make a black-and-white background while keeping the subject in color:

    Use ColorsDesaturate. In the dialog that opens, cycle between the modes and select the best-looking one, then click OK.

    图 3.44. Result of Desaturating the Background

    Result of Desaturating the Background