Cutting Corners Well

We should make a distinction between concave and convex corners. The corner where the wall meets the ceiling is an example of concave. Most walls in a room also meet in this concave fashion. The edge of a table is an example of a convey corner. These two types of corner must be painted differently.

A concave corner is not too much of a problem when painting. It might be hard to reach with a roller, so a small to medium brush must be used in the tight corner space. As long as there are no obvious lines where the roller paint and brush paint meet this can look perfectly fine.

A convex corner can cause problems when painting. The edge where the two surfaces meet cannot be too sharp because paint will not bond well to such a thin edge; nor will the undercoat. Instead this sharp edge must be softened. Often this can be so subtle as to be unnoticeable, and simply achieve with some sandpaper. Alternatively the corner may be deliberately rounded. This rounding must be very even or the result will look poor. A router can be used for rounding the edges of some items, though any edges on a wall will require a dedicated round sanding block. 

Some house interiors are designed and built with curved corners and cornicing’s. This looks especially stylish and makes painting edges a little easier. 
Sydney Painting
Corner preparation is one of many aspects of properly preparing a houses’ interior for painting.