What is often the result of applying a metal conditioner before painting?

Applying a metal conditioner before painting is primarily designed to enhance the surface of the metal, which significantly improves the adhesion of the paint. Metal conditioners typically contain phosphoric acid and other chemicals that clean the surface and provide a better profile for paint to cling to. This results in a stronger bond between the paint and the substrate, leading to a more durable finish. Improved adhesion helps to prevent issues such as peeling or chipping of the paint over time, ultimately contributing to a longer-lasting aesthetic appearance and protective quality of the paint job.

The other options do not reflect the intended purpose or effect of a metal conditioner. For instance, instant corrosion is the opposite of what a metal conditioner aims to prevent; it is actually used to protect against rust by treating the metal surface. Decreasing paint durability contradicts the use of a conditioner, which aims to enhance durability instead. Finally, while imperfections can be highlighted if the surface is not properly treated, the purpose of a metal conditioner is to help create a smooth, even foundation for painting, thus reducing the visibility of imperfections rather than increasing it.