4.10. Separere et objekt from dets baggrund

Figur 3.39. Objekt med baggrund

Objekt med baggrund

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.

The Free Select Tool allows you to draw a border using either freehand or straight lines. Use this when the subject has a relatively simple shape. Read more about this tool here: Afsnit 2.4, “Free Selection (Lasso)”

Figur 3.40. Fri markeringsværktøj

Fri markeringsværktøj
Fri markeringsværktøj

The Intelligent Scissors Select Tool lets you select a freehand border and uses edge-recognition algorithms to better fit the border around the object. Use this when the subject is complex but distinct enough against its current background. Read more about this tool here: Afsnit 2.7, “Intelligent Scissors”

Figur 3.41. Intelligent saksemarkeringsværktøj

Intelligent saksemarkeringsværktøj
Intelligent saksemarkeringsværktøj

The Foreground Select Tool lets you mark areas as Foreground or Background and refines the selection automatically. Read more about this tool here: Afsnit 2.8, “Forgrundsmarkering”

Figur 3.42. Forgrundsmarkeringsværktøj

Forgrundsmarkeringsværktøj
Forgrundsmarkeringsværktøj

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.