Using Decompose

3. Drawing a mask

	Brush Tool Paints a thick line - the thickness of the line can be adjusted with the "size" slider. Fill Tool Paints a closed region. Region Tool Paints a region defined by an arbitrary shape. Rectangle Tool Paints a region defined by a rectangle. Color Tool Paints all pixels with similar color - the tolerance can be adjusted with the tolerance slider.

The mask has three colors:

	Foreground Color Pixels of that color are fully part of the object you are trying to extract. Contour Color Pixels of that color are part of the background or the foreground (and sometimes both). You are asking Decompose to decide for you. Background Color Pixels of that color are fully part of the background you are trying to remove.

When you open your image, the default mask color is the background color. So typically, you will first trace the contour of the object with the brush tool with the contour color.

Then, with the Fill tool, you fill the object with the foreground color.

That's it! Note that at any time, you can use the Image/Mask slider to change the view between the original image and the mask. You are now ready to let Decompose do the rest of the work.