Erasing image areas

You can use the Eraser tool to erase areas of a layer to transparency. When you use the Eraser tool on a raster layer, all pixels in the tool’s path become transparent. A gray-and-white checkerboard pattern indicates transparent areas.

You can use the Background Eraser tool to erase pixels selectively. For example, in a photo of a mountain range, you can erase the sky, or you can isolate an object from the surrounding image area.

When you undo an action in Corel PaintShop Pro, the detail from the original image is restored. To understand the difference between undoing and erasing, consider the example of paint strokes. If you make a mistake with a paint stroke and erase it, the image detail under the stroke is lost. You can erase paint when you want to make certain pixels transparent. You can also erase to create an effect, such as when you want one layer to show through another layer.

You can adjust the default settings for the Background Eraser tool on the Tool Options palette. For example, you can change the opacity, color tolerance, and sample area settings.

You can set the following controls when you use the Background Eraser tool:

• Opacity — specifies the level of opacity. A setting of 100% erases pixels to complete transparency, and a lower setting erases pixels to partial transparency.

• Tolerance — determines how closely the selected pixels match the sampled pixel. The range of values is 0 to 512. At lower settings, only pixels with very similar colors are erased. At higher settings, more pixels are erased. (This option is unavailable if the Auto Tolerance check box is marked.)

• Sharpness —specifies how much the softness of the erased edge depends on the color difference between the object and the background. The range of values is 0 to 100. You can use lower settings when the edges that you are erasing form a gradient (a more gradual color transition); you can use higher settings when the edges that you are erasing have a more abrupt color transition.

• Sampling — specifies the basis on which pixels are erased. This control has the following options:

Once — samples the point at which you first click and then erases all matching pixels for the duration of the stroke. This setting erases similar colors and preserves the areas you want to keep.

Continuous — samples continuously and erases all matching pixels. If the area to erase is quite variable, you can use this option and set the Step value low, so that the area is sampled frequently as you erase. The tool can erase any color it encounters, including foreground colors if the sampled pixel falls into the foreground area.

BackSwatch — erases all pixels that match the current background color on the Materials palette

ForeSwatch — erases all pixels that match the current foreground color on the Materials palette

• Limits — specifies whether erased pixels are adjacent to each other. This control has the following options:

Discontiguous — erases all pixels in the tool’s path that match the sampled pixels, even if they are nonadjacent. You can use this mode to correct areas in which the background shows through holes in the image.

Contiguous — erases only contiguous pixels that match sampled pixels. You can use this mode when the background pixels are of a color that is similar to that of the edges of the object you want to isolate.

Auto Tolerance — determines the tolerance based on the pixels in the tool’s path. The tolerance may change continuously as the tool moves over different parts of the layer. You can unmark this check box to specify a Tolerance setting.

Use all layers — samples data from all layers merged together. Only pixels in the current layer are erased. To sample data from the current layer only, you can unmark the check box.

Ignore Lightness — ignores sharp differences in color lightness and saturation. You can 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.

You should start by marking the Auto Tolerance check box. If you find that too much or too little is erased from the image, you can unmark the Auto Tolerance check box and increase or decrease the value in the Tolerance box.

You can also
Restore erased pixels	Hold down the right mouse button, and drag over the erased area.
Erase a straight line	Click at the beginning of the line, hold down Shift, and click the end of the line. To continue erasing the line, move to the next point, hold down Shift, and click again.

If you erase the background layer, the Eraser tool erases to transparency, and the layer is automatically promoted to a raster layer.

1 On the Layers palette, click the layer that contains the image element that you want to isolate.

Slow, careful strokes give you the best results. Keep the center of the brush on regions you want to erase, while keeping the edges of the brush on regions you want to preserve.

You can also
Restore erased pixels	Right-click and drag.
Erase a straight line	Click once at the beginning point, hold down Shift, and click the endpoint. To continue erasing the line, move to the next point, hold down Shift, and click again.
Switch to the Eraser tool	Hold down the Backspace key while you drag the mouse.

The background layer is automatically promoted to a raster layer when you work on it with the Background Eraser tool.

You can preserve the transparent background (when you want to place the visible content on another layer or background) by saving your file in the following file formats: PSPImage, PNG, GIF.