Both lab finishing and blueprinting refer to the process used to insure the accuracy of the propeller rake angle, pitch, progression, pitch variation and cup. This hand process involves thinning the blades and sharpening the leading edges.

The advantage of blueprinting is that it reduces the horsepower required to turn the propeller and generates more usable horsepower for thrust. On an accurate, well-built propeller the speed gain may be 2-3 miles per hour. On a lesser quality propeller, the increase may be 3-4 miles per hour as an average, I have pulled as much as 12 mph out of one particular propeller.