Photoshop Eraser Tool

 Photoshop's eraser tool can be found in the second group of icons in the toolbox. It has three variations: Eraser,Background Eraser and Magic Eraser.

The eraser is basically a brush which erases pixels as you drag it across the image. Pixels are erased to transparency, or the background colour if the layer is locked.

When you select the eraser tool, you have various options available in the toolbar:

Brush: Options include the size of the eraser, hardness of edges and various styles. Brush options are not available in block mode.

Mode: There are three options: brush (soft edges), pencil (hard edges) and block (square brush size).

Opacity: 100% opacity erases pixels completely, 0% does not erase at all. 50% is semi-transparent (or coloured). Opacity is not available in block mode.

Flow: Determines how quickly the erasure is applied by the brush. Lower settings produce a more subtle effect. Only available in brush mode.

Airbrush: Use the eraser as an airbrush. Only available in brush mode.

Erase to History: Erases to a saved state or snapshot of the image. To use this feature, click the left column in the history palette next to the desired state.

Background Eraser Tool:

 The background eraser tool allows you to remove the background colour from an image or layer. When you click the image, the eraser samples the colour at the centre of the brush and erases this colour as you drag. Options in the toolbar allow you to specify the type of erasure, colour tolerance and sampling method.

Magic Eraser Tool:

 The magic eraser tool erases all colours within a set tolerance. This is essentially the same as using the magic wand and hitting Delete. Using this tool you don't need to drag — just click once.