Paint correction is a term that is used to describe the process of restoring and rejuvenating the paintwork of a vehicle, mostly through the elimination of surface imperfections, that dull, oxidize, or haze the surface by reflecting light off in various directions, therefore detracting from a true and proper, clean, sharp, reflection. These imperfections include things like swirl marks & fine scratches, bird dropping etching & acid rain etching, hologramming & buffer trails, and random isolated deep scratches (or RIDS).
The term paint correction should only really be used if these imperfections are properly removed and are not just merely covered up or hidden with filler based products. The actual corrective process itself comprises of a small amount of clear coat or paint being removed from the surface with the use of abrasive polishes, which are applied and worked in with appropriate polishing machines, in order to level out the surface.
Before any paint correction is undertaken, a thorough wash and decontamination of the vehicle is performed. Paintwork is properly washed and cleaned to remove any loose dirt and debris, then after the wash process is clayed with a specialist automotive clay bar, which safely removes any bonded surface contaminants such as tar spots and industrial fallout.
It is important these contaminants are removed before the paint correction process because if they were to become dislodged and caught up in the pad of a polishing machine, they could easily inflict damage onto the surface very quickly. It also helps to leave the surface very smooth, which in turn, allows the polishing machine to move freely over the surface, reducing the possibility of hopping or sticking occurring. Lastly, claying the paintwork helps you to properly observe the progress of the correction process because you can see the true condition of the surface as you are working.
The polishing is usually a multistage process as a range of different polishes are used, ranging from heavier cutting compounds, which remove the surface material, to finer products which then remove any marks that the heavier products may have inflicted and generally refine the finish.
Some scratches or imperfections may actually be too deep or severe to safely remove without risking removing to much surface paint or clear coat and so are minimized and reduced as best as possible using techniques with the rotary or dual action machines and polish products that round off the edges of the scratches and make them far less apparent in direct light.