Depending on the colour of the car and the finish of the paint e.g solid, single stage, met colours, pearls they will approach it differently.
Basically they will paint what they think is the colour on the car (as given by paint code and scans) this will cover the damaged area, they will then fade this out over the good bit of the car, to blend the colour difference so its not noticeable.
Then this is where is changes between smart repairs and proper repairs. Proper repairs will then lacquer the whole panel affected. Smart repairs will cover as little as possible and then use blend out spray (this is basically thinners in a can, which attacks your lacquer and damages it, to get rid of the nasty masking lines, this is the main reason they fail after a short period of time)
There are so many variables which change the colour of the paint they are applying, like hand speed, distance from the panel, static on the car and sprayer, amount of car to spray, type of undercoat and lacquer, type of spray gun, manufacture of the paint, base and lacquer.
To put it simply, the paint they put on won’t match the rest of the car. How much you notice it, depends on how good the person doing it is!!!
Good luck with it