Paint correction is the process of renovating and restoring a cars paint by removing surface imperfections, that otherwise dull or haze the surface and result in a dull, matt paint finish. These imperfections include light swirl marks or scratches from improper washing, bird droppings or industrial fallout.
The actual process of removing these imperfections, is to remove a fine (microscopic) layer of clear coat lacquer using a dual action polishing machine and various polish compounds to bring the level of the lacquer down to the swirl mark or fine scratch so that the overall lacquer level is completely matched, therefore making it visually disappear.
It is important to prepare the paint before any paint correction. This means thoroughly cleaning and removing any contaminants with a clay bar to allow a smooth clean surface to work on. The clay bar is a helpful tool, as it allows you to visually see the dirt and gives you the confidence that the paint work is totally contaminant free.
During the paint correction process it is common for a paint depth gauge to be used. This measures the thickness of the paint and allows you to monitor the amount of material being removed and prevents the paint becoming too thin. Other tools used to aid the process would be a specialist halogen or LED lamp that replicates direct sunlight. This process allows you to check if the swirl marks have been removed completely, and you can move onto the next panel.
The entire process is normally the most labour intensive stage of detailing, and consequently demands a higher premium from professional detailers and valetors. I always advise that amateurs or enthusiasts should trial by buying a test panel from a scrap yard or test a small inconspicuous section of their own car before attempting bigger panels
A professional paint correction should reveal a mirror like shine which offers a perfect shine from any angle in and light.