This GIMP (GNU) tutorial demonstrates how to extract an object’s background using GIMP’s Scissors Select Tool. To work along, you are welcome to download the Start Image I am working with Here. Unzip the file and open the image onto GIMP’s workspace.
Scissors Select Tool Notes
The Scissors Select Tool (Intelligent Scissors Tool) has some features in common with the Free Select Tool, some features in common with the far superior Paths Tool, and some features all its own. It is useful when you are trying to select a region defined by strong colour changes at the edges. To use the Scissors Tool, you click to create a set of "control nodes", also referred to as Anchors or Control Points, at the edges of the region you are trying to select. The Tool produces a continuous curve passing through these control nodes, following any high-contrast edges it can find. If you are lucky, the path that the Tool finds will correspond to the contour you are trying to select. Each time you left-click with the mouse, you create a new control point, which is connected to the last control point by a curve that tries to follow edges in the image. To finish, click on the first point (the cursor changes to indicate when you are in the right spot). You can adjust the curve by dragging the control nodes, or by clicking to create new control nodes. When you are satisfied, click anywhere inside the curve to convert it into a Selection Marquee.
You can quickly Undo a step at any time by pressing Ctrl then Z. Alternatively, click a previous Undo History snapshot - Windows then Dockable Dialogues then click Undo History. In addition, to Zoom in (or Zoom out) of your image; from the top menu, choose View then select a Zoom Tool from the subsequent drop-down
Launch GIMP & Organise Its Workspace & Palettes
Open your choice of Start Image onto GIMP’s workspace - File then Open - Ctrl then O.
Ensure the Layers and the Undo History Palettes are visible, and then drag them into position over your workspace - (Windows then Dockable Dialogues - then click Layers and Undo History).
2/ Add An Alpha Channel
Now, from the Layers Palette: right-click over the Background Layer, and from the subsequent drop-down list, click Add Alpha Channel.
Then from the left-side Toolbox, activate the Scissors Select Tool.
And ensure the following (default) settings are active in the Tool’s Options Box.
You will find the pepper’s extraction much easier if you enlarge your image by Zooming into it.
I zoomed in once.
You are looking to isolate just the pepper’s edge with a lasso line (Path).
Therefore, left-click once anywhere along the pepper’s edge. This applies your first control point, as illustrated below.
At this point, it’s not crucial that your Path is perfectly positioned. This is because, before closing the Path, you can go back at any time and edit it.
After applying your first anchor point, left-click and apply a second control point a little further along the pepper’s edge - as illustrated below.
Beginners, you will find this much easier if you apply your Control Points fairly close together.
Now, continue to left-click and apply multiple control points around the pepper’s edges.
Remove The Path
To remove the Path, press the Escape Key.
After you have clicked a Path completely around the pepper, left- click over the very first Control Point - as illustrated below. This closes the Path.
Congratulations, you have applied a Path around the pepper’s edges, and you are ready for the next step.
4/ Reposition The Path
Left-click over your choice of anchor point, and gently tug it. This moves the Path as if it where soft wire.
Now, with your mouse, gently reposition the Path so that it closely hugs the edge of the pepper - as illustrated below.
Then continue to reposition the Path so it closely hugs the pepper’s edges, by (one at a time) gently tugging the relevant control point. After you have completed this, you are ready for the next step.
5/ Convert The Path Into A Selection
To convert the Path into a Selection: left-click once inside the Path - (over the pepper). This converts the Path into a Selection Marquee - as illustrated below.
6/ Shrink The Selection Marquee
Now, right-click over the selected pepper, and from the subsequent drop-down list, click Select and then choose Shrink. Now, from the subsequent Shrink Selection dialogue box, set a Shrink selection by setting of around 2 Pixels, and then click OK.
Return your image to its original size - View then Zoom then Zoom Out.
7/ Feather The Selection Marquee
Now, right-click over the selected pepper, and from the subsequent drop-down list, click Select and then choose Feather. Now, from the subsequent Feather Selection dialogue box, set a Feather setting of around 5 Pixels, and then click OK.
8/ Invert The Selection Marquee
From the top menu, choose Select and then choose Invert - Ctrl then I. This inverts the Selection Marquee.
Then from the top menu, choose Edit and then choose Clear. Alternatively, tap your Delete Key. This deletes the pepper’s background - as illustrated below.
From the top menu, choose Select and then choose Select None. This removes the Selection Marquee.
Congratulations, you have successfully extracted the pepper from its background using the Scissors Select Tool, and it is ready to Crop to size, and to optimise and save.
Drop Shadow Tip
My Tutorial Here demonstrates how to apply a Drop Shadow - Filters then Light and Shadow then Drop Shadow.
Transparent GIF Tip
Link Here to learn how to save your Transparent Image as a Transparent GIF.
Fill Layer Tip
My Tutorial Here demonstrates how to create a Fill Layer and Fill it with either a Solid Colour, Pattern or a Gradient.
To create extra impact, apply a Sharpening Filter of your choice - Filters then Enhance.
My Tutorial Here demonstrates how to resize object/images.
To finish, from the top menu, choose Image and then choose Flatten Image.
Now you are more familiar with this technique, you can have lots of fun removing backgrounds from your favourite images, objects, or photographs.
Wendi E. M. Scarth. Top of Page.