Sometimes paint work can appear a different colour around the wall edge.
The appearance of different colours around the edge of walls (hence the term picture framing) is generally the result of using different application methods to complete a project. For example, applying a first coat by brush and a second by roller. Colour difference may also occur if the paint hasn't been stirred through thoroughly.
Always double check that the coating spread rates are similar with both brush and roller application. When painting large areas, work in smaller sections and don't cut in an entire room before roller coating.
You should also always check that tinted paint has been coloured correctly, shaken thoroughly and then stirred if necessary.