Scratch Removal Tool

The scratch removal tool lets you remove straight or curved scratches or other linear features such as telephone wires in the image by writing over the scratch with image data from the surrounding area.

You have the option of removing scratches lighter or darker than their surrounding neighborhood, or both.

Defining scratches

To start a new scratch initially:

Shift-click on the input image at one end and drag the cursor to the other end. Or, you can shift click at one end of the line and then shift-click at the other end. This displays an overlay over the input image like the following:

The rectangle indicates the area that will be replaced by interpolating data from either side of the line. For best results, the scratch should be just enclosed in the rectangle. You can adjust the scratch radius using either the Scratch Radius slider or using the mouse scroll wheel.

To select a scratch:

Click on one of its control points. When a scratch is selected, its outline is displayed. To deselect a scratch, click on the input image away from any of the control points. When a scratch is deselected, its is displayed as a thin line through all of its control points.

      selected              deselected

When you select a scratch, the Scratch Radius, Scratch Strength, Remove and Method settings are updated to reflect the properties of the scratch.

To add control points to a scratch:

If you have not selected a scratch, first click on one of its control points to select it. You can skip this step if the scratch is already selected. To make the scratch curved instead of straight, add control points along the curve as illustrated below.

Shift-clicking on the input image adds a new control point at the location you clicked. You can add as many control points as necessary to control the shape of the scratch.

When you add a new control point to an existing scratch, it is inserted between two nearby control points. If you click beyond either end of the curve, it is extended. If you click too far from the curve, you may not get the insertion point you want, so a better way is to click between two existing points and then drag the new point where you want it.

To start a new scratch:

First deselect all scratches by clicking away from any of the control points. Then Shift-click on the input image at one end and drag the cursor to the other end.

To remove a control point:

Ctrl-Click near the control point. When you get down to one control point, the entire scratch is removed.

To remove an entire scratch:

Ctrl-Shift-Click near any of the control points of the scratch.

Amount

The amount control lets you scale back the overall scratch removal or you can create a mask to restrict scratch removal to specific parts of the image.

Scratch Radius

This slider lets you control the scratch radius in pixels for the current scratch. You can also vary the scratch width with the mouse scroll wheel.

Scratch Strength

This slider lets you control the what percentage of the current scratch is removed. The default value is 100%, but if, for example, you are using this tool to reduce reflections in a portrait, you can lower the strength so it leaves part of the highlight but makes it less obvious.

Scratch Softness

This slider lets you control the softness of the edges of the replacement for the scratch. At 0% the transition at the edges of the scratch are abrupt -- at 100% the edges are heavily blended.

Remove

This control lets you select whether you remove the current scratch if it is lighter than the background, darker than the background or both. If the scratch you are removing is consistently darker or lighter than its background, using the corresponding remove mode will produce fewer artifacts.

Method

You have a choice of two different scratch removal methods.

Interpolate -- this method fills in the scratch by interpolating image data from either side of the scratch. This method works better if the background behind the scratch is smooth and more or less without texture.

Clone -- this method copies patches of image data from either side of the scratch to cover the scratch. This method works better if the background is heavily textured.

Tips

The more tightly you can enclose the scratch, the better the result. While using a larger radius makes it easier to click on scratches, a smaller radius produces fewer artifacts.

The scratch removal tool may not do as good a job erasing part of a scratch near the edges of the image if it does not have image data on either side of the scratch.

If you are working on a large image, to avoid response time delays, you may find it useful to turn auto preview off until you have finished marking all the scratches. Long scratches can take some time to remove.