Cloning; To Clone; Cloned; Clone Tool;
In digital image processing the clone tool is used to copy one part of an image over another part. The term cloning is the act of carrying out the cloning process.
Typically the act of cloning involves removing parts of the image that are unwanted. The clone tool is set up by first picking a source area of the picture. Then a painting tool is used to paint a copy of the source area over the destination space. The act of painting replaces the destination space leaving behind a replica of the source area.
Normally a cloning tool has several adjustments although this will vary depending on the application. Adjustments may include:
- Size of paint brush
- Feather of the edges (varies from a hard edge to soft graduation)
- Opacity – how strong the paint effect is:
100% = one stroke – total coverage – opaque result.
25% = a quarter stroke – background shows through
@ 25% 4 strokes = 100% coverage.
- Flow – rate of coverage given by a stroke.
An array of different types of clone tools exist. The clone tool described above is a simultaneous copy-and-paint tool. There are also ‘spot’ tools. These can grab surrounding pixel colours and textures and delete a small spot or line with the grabbed pattern. History tools can be used to access the previous history of edits and clone back the originals. Patch tools can take a predefined area of the image and patch it over a destination place on the image. Healing tools can be used to intelligently copy a coloured/textured area and paint it over the destination space so it blends in using the appropriate brightness, colours and textures. A variety of different options exist for these tools as well as other variations on the theme (application dependent).
Clone tools date back to the first painting applications in the 1980s. Originally they were used to ‘rubber stamp’ patterns onto the page. The patterns were presets or could be loaded. Today these tools have evolved and computers have developed more power to resource them. Clone tools today have ‘rubber stamp’ icons in some applications acknowledging their history.