The third tool in this tool group is the smudge tool. You may notice that the symbol for this tool is a hand with an extended finger. This is because the Smudge tool simulates the effect of smudging or smearing colour with your finger tip.

If you imagine the colour in a given bitmap image as being made from wet paint, using the smudge tool is like drawing and distorting the wet paint as you drag your mouse pointer over the image. The image colour will be smudged in the direction that you drag your mouse pointer.

The smudge tool has the same options available in the options bar as the blur and sharpen tool. You can modify the brush type and size, the strength of the smudge effect, the mode, and whether it involves all layers or only the active layer.

The smudge tool should not be confused with the blur tool. The blur tool makes a selected edge or area of contrast appear out of focus. The smudge tool draws the colours in a way that distorts or warps the edge or area of contrast.

The smudge tool will have now effect on the image if the mouse pointer is not dragged, whereas the blur tool (and sharpen tool) will alter the image (under the mouse pointer) as long as the mouse button is held. As with the blur and sharpen tool, you can adjust the opacity of the smudge effect by choosing Edit->Fade Smudge Tool.

The foliage on the palm tree on the left has been smudged, while the tree on the right remains untouched.