When painting a room, it's important to pay special attention to the corners to avoid visible lines or banding between the walls and corners. To achieve a seamless finish, it's recommended to use the same painting tool on the corners as you use on the walls to prevent any textural discrepancies.
If you are using a roller on the walls, use a small trim roller for the corners. If you prefer to use a brush on your walls, use one for the corners as well. This will help ensure that the corners are painted evenly and have the same texture as the walls.
Banding can occur when a specific area (such as a corner) is painted and allowed to cure before the wall paint is applied. To prevent banding, it's important to paint the corner directly before or after coating the wall, so the layers of paint dry at the same rate.
Additionally, ensure that the corner and the wall have the same amount of paint and number of coats applied to them. If one area receives more paint or an additional coat, it will look noticeably different. When painting corners between two walls, there is a natural tendency for more paint to build up in the corner, making it appear darker. To avoid this, make sure to apply paint evenly to the corner and walls.
If the corner section appears lighter, you might have missed a coat or your tools may not be effectively laying paint right into the corner. In this case, reapply a coat of paint to the corner to achieve an even finish. - MitchellMc