Free Select

Free Select, Scissors Select and Paths Select tools

The rectangle and ellipse selection tools are not as useful as you might think since pure rectangular or elliptical shapes occur rarely in photographs. To select more complex shapes the Gimp proposes three tools:

• The free select (lasso) tool is easy to understand but not as powerful as the paths tool.
• The scissors select tool is easy to use but often produces a selection with scruffy edges - it's usually not the best choice.
• The paths tool is the tool I recommend you use most of the time to select irregular shapes. It gives a selection with clean edges, is not too difficult to use but is sophisticated and powerful.

In a moment, some details about using each of the tools, but first some general comments:

Don't forget to set feathering and antialiasing before you use each tool, as explained in the Selections page. Before you use the free select or scissors select tool, it's a good idea to zoom in (press '+') as much as you can while making sure that all the area you wish to select remains visible. This will help you make an accurate selection. Making an accurate selection with these tools can take quite a long time - but if you want to do a good job then you may not have much choice.

To use the free select tool just drag around the edge of the area you want to select. Double-click to close the selection. Accurate use of the free select tool in that way is much easier said than done however. Alternatively, you can use this tool by click, click, clicking your way around the area you want to select (double-click to close the selection). You can even combine these two techniques (click, click, drag etc). All this is easy enough, but the paths tool (see below) works in a similar way and gives you more power, so why not use it instead?

To use the scissors select tool just click, click, click your way around the shape you want to select - the more clicks you make the more accurate your selection will be but in any case the GIMP will help you by trying to detect the edges of the shape (by looking for the contrast between lighter areas and darker areas). You can adjust the position of the nodes (the 'click-points') by dragging them (except for the first node). To close the shape, click on the first node (which you can then move). You will now have a collection of nodes - one node for each place that you clicked. You can continue adjusting these nodes by dragging them and you can add new one's by dragging any point on the line. If you aren't satisfied then press Escape and start again. When you are satisfied, click inside the shape in order to make it into a selection. Even the scissors select tool is not ideal however, for it often does a poor job finding the edge of the shape, leaving you with a scruffy-edged selection.

Is there no tool capable of giving a clean-edged selection? Yes! The GIMP includes a very powerful paths tool which can do this - this is the tool which we will focus on now...

Test your selection skills by using the path tool to select Sugar, the dolphin in the photo below. Select the paths tool in the toolbox or press 'b' on the keyboard or choose Tools>Paths. The paths tool is so sophisticated that I suggest you limit its power the first time you use it (you wouldn't want to have driving lessons in a Porsche 911 would you?). So turn on the tool's 'polygonal' option - this will limit you to making a polygonal selection - not an obvious move when you want to select a dolphin - but the polygon can follow curved edges well enough if you make enough clicks. Start clicking your way around the dolphin, then - I'm expecting you to take your time on this and make about 40 clicks altogether. You can also click-drag to adjust the position of each click. Your work will be easier if you expand the picture to fill you screen (double-click the picture's blue title bar then do View>Zoom>Fit Image in Widow or Ctrl+Shift+E). If you want to zoom in further on the dolphin then type '+' on the main keypad. Ignore the hoop as you click your way around the dolphin. When you get back to the beginning stop and examine the path you have created. If you want to move a node, just drag it. If you want to add additional nodes (each point is called a node) you can, by Ctrl+clicking the path. If you want to delete a node then Ctrl+Shift+click it. When you have finished making the path you should convert it to a selection by clicking the corresponding button in the tool's option window.

Let's shrink the new dolphin to make it look like mother and baby are jumping through the hoop together. Choose the Scale tool (or press Shift+T). You probably don't want to change the shape of the dolphin, only its size, so hold down the Ctrl key as you drag a corner handle to resize the dolphin. Press the Scale button when you have the size you want. Switch back to the move tool (press 'm') and drag the baby dolphin into a location such that the hoop looks 'natural'. Save your finished image in the jpeg format (and also in the XCF format if you think you may want to modify it later).

If you'd like to visit Sugar, he lives in Sugar Key, one of the Florida Keys...

In this lesson you have only used the path control with the polygonal option turned on, meaning that you were only able to create a shape with straight sides. The next step would be to use the tool with the polygon option turned off - each segment of the shape could then be given a curve. This is time-consuming, however, and a bit complicated and difficult so it is not covered in this course. However, if you think you are ahead of your classmates then you are more than welcome to explore the full power of the path tool - check section 6.1 of the Gimp help system to get started.

In this lesson we have done a pretty good job in manipulating a photograph so that it presents an image of something that never was. This is deceptive, of course, and you should be starting to think to what extent it is morally acceptable to manipulate images in the way that I am teaching you. A few years ago there was a scandal when two magazines used the same photo on their covers - a photo of a suspected criminal. The scandal happened because one of the magazines had manipulated the photograph to make the person look more evil than he looked in the original... Make no mistake - MANY of the photos you see in magazines have been manipulated. Stop Press: I just noticed that today the BBC website is carrying a story called 'Sacking call over doctored photo' - the article is about how a UK Conservative party candidate modified a photograph for political reasons, leading to calls for his resignation. Are we playing with fire??