Should arch between 2 rooms be painted the color of one of the rooms or totally different?

The arch between two rooms can be painted the color of one of the rooms to create a cohesive look or a different color to serve as a visual bridge that highlights the transition. Choosing the same color can enhance harmony, while a contrasting shade can add interest and define the space. Ultimately, the decision should align with your overall design aesthetic and the atmosphere you wish to create in your home.