You have two three simple ways of clearning an image:
Click the Clean button
on the toolbar.Click the File menu and choose "Clean".
Using the Control-G (ie. pressing the “Ctrl” and “G” keys at the same time) shortcut key.
For all these options, a small progress dialog will popup showing the progress of the cleaning process. It is normal that the progress bar may stop for a few seconds and then start moving again.
The processing time depends on the size of your image and the speed of your computer. On a desktop with 1 GHz Pentium 4 CPU and 128 MB RAM, it usually takes around 10 seconds to process an image with a size of 1568x1024 pixels.
If you are not satisfied with the processing, you can undo the the processing and return to the original image by either selecting "Undo" from the Edit menu or clicking the "Undo" icon on the toolbar.
If you feel that some lines in your image appear too light or too dark, you can change the contrast via the "Contrast" setting in the preferences. The "Contrast" option is found under Edit/Preferences/Contrast menu. The range of contrast is between 0 and 80. The higher the value, the higher the contrast. We recommend 20 for most photos. Check the following table for the results of different level of contrasts.
By default, a cleaned image keeps its original resolution and aspect ratio. You can easily scale an image using the Scale item under the File menu.