Within.

Since my pictures are large, colorful, and unframed, and since museum walls are usually immense and formidable, there is the danger that the pictures relate themselves as decorative areas to the walls. This would be a distortion of their meaning, since the pictures are intimate and intense, and are the opposite of what is decorative; and have been painted in a scale of normal living rather than an institutional scale. I have on occasion successfully dealt with this problem by tending to crowd the show rather than making it spare. By saturating the room with the feeling of the work, the walls are defeated and the poignancy of each single work...become[s] more visible.

I also hang the largest pictures so that they must be first encountered at close quarters, so that the first experience is to be within the picture. This may well give the key to the observer of the ideal relationship between himself and the rest of the pictures. I also hang the pictures low rather than high, and particularly in the case of the largest ones, often as close to the floor as is feasible, for that is the way they are painted. And last, it may be worthwhile trying to hang something beyond the partial wall because some of the pictures do very well in a confined space.
- Mark Rothko

Rothko, No. 10, 1950