Desktop FDM 3D printer has the largest market shares, among which the single-extruder printer is preferred for its low price. However, it's hard to see the details of monochromatic prints. But if you own a dual-extruder 3D printer, it will be looked like creating things on a white paper with a black pen.
Solution
Step 1: The first thing you need to do is to separate each color of the model to be printed into individual STL objects and assign each to a particular extruder.
Step 2: Before the printing can start, the printer needs to be told which part is to be in which color. We need to assign colors to a particular extruder with software like MakerWare.
Step 3: After setting the STL objects, the model is combined and sent to the 3D printer.
Step 4: The two separate objects are then printed in a single pass which combines automatically as the print nears completion.
Step 5: Break the supports with graters and polish with sandpaper.