Pen Tool in Photoshop

Adobe Photoshop is the industry leader for manipulating the square pixels which make up bitmap images. The pen tool works in a completely different way, creating 'vector' based paths made up of straight lines and Bézier* curves controlled by points and handles. These are very useful once you are proficient with them, and are the basis of whole graphics programs such as Illustrator, Freehand and CorelDraw. Even QuarkXPress 4 has some quite useful path creation tools. Paths are very powerful and professional designers know how to draw and edit them.

In Photoshop, paths can be useful to define a line which you 'stroke' or 'fill' with paint. You can convert a drawn path into a selection, or create a clipping path to remove the background from something when the photograph is saved as an EPS (Encapsulated PostScript) file and then placed into a layout package such as InDesign, QuarkXPress, Pagemaker or Freehand.

When you first select the pen tool, decide whether you want a shape layer (the left hand choice) or a conventional path (the highlighted darker grey choice with a pen tool symbol shown above). If Auto Add/Delete is ticked you don't need to keep going back to the toolbox to change tools, just use the normal pen and it changes automatically to add a point if you are over a highlighted line, or to delete if you are above a highlighted point.

The 4 options to the right of Auto Add/Delete are about how you want two or more shapes to add, subtract or intersect each other.

Click to add a point, click and drag in the direction of your next point to add a curve. Try to go just inside the edge of your picture to prevent an unwanted halo around the edge.

The pen tool has other options hidden behind it - the most useful being the Convert Point Tool shown at the bottom of this list. Click on a point to make the control handles disappear, making it a corner point, or click and drag to make a curve point. Rather than having to go back and forth to the toolbox, use the shortcut of holding down the 'alt' key to temporarily change the pen tool to the convert point tool. When you release the 'alt' key the tool will change back to the pen tool.

Above the pen tool icon in the Toolbox is a pair of arrows. Use the Solid Black arrow to move the whole path. Use the White arrow to select individual points to move them around.

*Why a Bézier curve? In the 1960s Renault engineer Pierre Bézier discovered that a class of Bernstein's polynomial equations were ideal to describe a spline curve to a computer in order to form car panels. The curves are very flexible, easy to edit and efficient at a computing level. Adobe's PostScript technology extends the use of these flexible curves to the outlines of type and to all graphics drawn as vector paths in programs such as Illustrator or its competitors Freehand and CorelDraw.