Fine details and texture
Final passes are lighter value and with a small brush, when I dive into whatever level of detail and finish I need. (If I want fine detail in a shadow area, I go with a medium value and its matching lower layer, and a small brush.) I match detail brush size to resolution: at 300dpi, a 10-pixel brush is 1/30th of an inch – tiny. There’s no need for details smaller than that.