Eraser tool

The eraser tool behaves in two ways depending on whether it is being used on the background or a layer. When used on the background layer, it removes pixels from an image, replacing them with the current background swatch color . When used on a layer it simply removes pixels making that area transparent; the degree of transparency is set by the Opacity slider in the tool Options bar and there are three brush modes: Brush, Pencil and Block. If you check the Erase to History box, the eraser behaves like the history brush and will paint from the currently selected history state in the History panel and holding down Option/Alt key as you paint will also erase to the currently selected history state.

The Flow option is only available when you erase using the brush mode. Above all, remember that the eraser tools are destructive, so if you are using the background eraser to make a cutout, it is probably a good idea to first duplicate the layer you are going to erase in case you need to recover the original pixels again. In fact, in nearly every case it is probably best not to use the eraser tool at all and use a layer mask to hide or reveal the contents of a layer. To find out more about how to use layer masks in this way, please refer to chapter 9 of the book.

Figure 1 The eraser tool Options bar.