Using the Background Eraser Tool

Use the Background Eraser tool to selectively erase pixels. For example, in a photograph of a mountain range, you can erase the sky.

To use the Background Eraser tool:

1. On the Tool palette, choose the Background Eraser tool . (It's grouped with the Eraser tool.)

2. On the Tool Options palette, choose the brush tip, size, opacity, hardness and other options. See Setting Brush and Paint Options. For the opacity setting, 100% erases pixels to complete transparency and a lower opacity erases pixels to partial transpar­ency.

3. Choose from these additional options:

4. Tolerance How closely the selected pixels must match the sam­pled pixel. The range is 0 to 200. At lower settings, only pixels with very similar colors are erased. At higher settings, more pixels are erased. (Note that this edit box is unavailable if the Auto Tolerance check box is marked.)

5. Sharpness How much the softness of the erased edge depends on the color difference between the object and the background. The range is 0 to 100. Use lower settings when the edges you're erasing form a gradient (a more gradual color transition). Use higher settings when the edges you're erasing are have a more abrupt color transition.

6. Sampling How the tool determines what pixels to erase:

Once samples at the center of the brush where you first click and erases all matching pixels for the duration of the stroke. Continuous samples at the center of the brush at every step and erases all matching pixels.

BackSwatch erases all pixels that match the current back­ground color on the Materials palette rather than sampling from the image.

ForeSwatch erases all pixels that match the current fore­ground color on the Materials palette rather than sampling from the image.

• Limits Whether erased pixels must be adjacent to each other:

Discontiguous erases all pixels in the tool’s path that match the sampled pixels, even if they are discontiguous (non-adja­cent). Use this mode on images that show the background through holes in the image.

Contiguous erases only contiguous pixels that match sampled pixels. Use this mode when the background pixels are close in color to the edges of the object you want to isolate.

FindEdges finds restricts the brush erasing according to the edge information.

• Auto Tolerance Mark this check box to have the tool determine the tolerance based on the pixels in the Background Eraser tool’s path; the tolerance may change continuously as the tool moves over different parts of the layer. Clear this check box to have the tool use the Tolerance setting that you choose.

• Sample merged Mark this check box to sample data from all layers merged together; only pixels in the current layer are erased. Clear the check box to sample data from the current layer only.

• Ignore lightness Mark this check box when the colors in the object that you want to isolate are strongly saturated and the background is unsaturated, or vice versa.

4. If the image has more than one layer, on the Layer palette click the layer that has an object that you want to isolate by erasing the background.

Note: The Background Eraser cannot be applied on the back­ground, which does not support transparency. If you apply the tool to the background, you are prompted to promote it to a full layer.

5. Drag on the layer, around the edges of the subject to erase the background area as follows:

6. To erase pixels, drag with the left mouse button.

7. To erase a straight line, click once at the beginning point, then press Shift and click the end point. To continue the straight line, move to the next point and press Shift and click.

8. To restore erased pixels, drag with the right mouse button.

Related Topics

Cloning Parts of Images

Creating Brush Tips

Erasing

Painting with the Paint Brush or Airbrush

Replacing Colors

Setting Brush and Paint Options

Using Brush Tips