Color Allocation and tk colormodel

In Tk 3.6, color allocations could fail if the colormap was full. In this case, Tk would revert its colormodel to monochrome and use only black and white. The tk colormodel command was used to query or set the colormodel. In Tk 4.0, color allocations do not fail. Instead, the closest possible color is allocated. Because of this, the tk colormodel operation is no longer supported. Use the winfo visual command, which is described on page 624, to find out the characteristics of your display.