The biggest problem I face with vehicle refinishing is colour matching. It’s a moving goalpost.
As soon as the car leaves the factory it’s bombarded by the elements particularly the radiation coming from the sun. It cause subtle changes that only become apparent when a repair is carried out.
Add to that the make up of the materials in modern cars all these factors can change the way the paint appears to the eye. A plastic bumper and a metal wing painted at the same time, in the same way, with the same paint, in the same oven can look completely different.
To help combat this most modern paint finishes consist of at least two different products. A matt finish base coat and a clear (laquer) top coat. This allows some degree of manipulation of the colour as the matt coat does not have to provide a high quality finish, this is achieved with the clear top coat.
Where possible an area of a panel is usually used to blend out the colour so the eye cannot detect a variation. This means adjoining panels to the one being repaired or replaced, are often painted to allow colour matching to take place.
This involves spraying the edge of the adjoining panel in the same colour as the repaired/ replaced panel and then apply less and less over the rest of that panel. The end result is there is a heavy coat of colour close to where the panels meet but ending up with no colour at the end of the panel where it joins the original colour of the car. The finish is then achieved by painting both panels with a clear top coat.