The Eraser tool changes pixels to either the background color or to transparent. If you’re working on a background or in a layer with transparency locked, the pixels change to the background color; otherwise, the pixels are erased to transparency.
You can also use the eraser to return the affected area to a state selected in the History panel.
An opacity of 100% erases pixels completely. A lower opacity erases pixels partially. See Paint tool options.
To temporarily use the Eraser tool in Erase To History mode, hold down Alt (Windows) or Option (Mac OS) as you drag in the image.
Photoshop performs intelligent smoothing on your brush strokes. Simply enter a value (0-100) for Smoothing in the Options bar when you're working with one of the following tools: Brush, Pencil, Mixer Brush, or Eraser. A value of 0 is the same as legacy smoothing in earlier versions of Photoshop. Higher values apply increasing amounts of intelligent smoothing to your strokes.
Stroke smoothing works in several modes. Clicking the gear icon () to enable one or more of the following modes:
Pulled String Mode
Paints only when the string is taut. Cursor movements within the smoothing radius leave no mark.
Stroke Catch Up
Allows the paint to continue catching up with your cursor while you've paused the stroke. Disabling this mode stops paint application as soon as the cursor movement stops.
Catch-Up On Stroke End
Completes the stroke from the last paint position to the point where you released the mouse/stylus control.
Adjust For Zoom
Prevents jittery strokes by adjusting smoothing. Decreases smoothing when you zoom in the document; increases smoothing when you zoom out.
When you click in a layer with the Magic Eraser tool, the tool changes all similar pixels to transparent. If you’re working in a layer with locked transparency, the pixels change to the background color. If you click in the background, it is converted to a layer and all similar pixels change to transparent.
You can choose to erase contiguous pixels only or all similar pixels on the current layer.
The Background Eraser tool erases pixels on a layer to transparency as you drag. You can erase the background while maintaining the edges of an object in the foreground. By specifying different sampling and tolerance options, you can control the range of the transparency and the sharpness of the boundaries.
If you want to erase the background of an object with intricate or wispy edges, use QuickSelect.
The background eraser samples the color in the center of the brush, also called the hotspot, and deletes that color wherever it appears inside the brush. It also performs color extraction at the edges of any foreground objects, so that color halos are not visible if the foreground object is later pasted into another image.
The background eraser overrides the lock transparency setting of a layer.
The Auto Erase option for the Pencil tool lets you paint the background color over areas containing the foreground color.
If the center of the cursor is over the foreground color when you begin dragging, the area is erased to the background color. If the center of the cursor is over an area that doesn’t contain the foreground color when you begin dragging, the area is painted with the foreground color.