If you are painting over a darker wall (like in the picture above) with a lighter colour, use a primer.
Can You Paint Over Painted Walls. A professional painter shares tips on how to paint over dark walls in your home including preparation, product and how to do it the right way! You paint walls first and skirting and baseboard are best painted after or even outside if it's good weather.
How to Lighten Paneling with Paint | how-tos | DIY from diy.sndimg.com
You can also use it over any edges that still seem harsh. Still, before adding heavy amounts of texture to your plaster applied over a painted surface should not be more than ¼ inch thick. Before you attempt to paint over a wall that already has paint, you need to prime the wall.
You can spray paint interior walls if you like speed, and outdoors too.
Wall paints should work for the most part, but i totally understand the need for more paint to blend with. If the paint on your wall is in good condition, then a professional will likely be able to start the plastering process straight away. Still, before adding heavy amounts of texture to your plaster applied over a painted surface should not be more than ¼ inch thick. You can complete some jobs much faster than other methods available by using a paint sprayer.
