In addition to the selection of magic wand in the painter, you can also use color selection to form a new channel, to convert to a selection, redefine the color. This technique in Photoshop may be familiar to everyone, is the color range of the command, painter can also do ...
1. Open the Channels (channel panel) of the Triangle hidden menu, select New from color range (the color range to get a fresh channel).
2. In the Pop-up Color Range dialog box, select the desired screen color with the eyedropper, and hook the inverted (invert) option so that the green range becomes the selection area, and the other is the Red mask area. The red on the mask is a range outside the selection. A new channel Alpha 1 is selected by color selection. If it is a previous version of painter 8, it is possible to select the color mask in the Mask panel to form a mask by selecting the colors.