Agnes Martin’s retrospective at the Tate shows a work of a lifetime that is extremely precise, controlled and for me represents separation from what is close. However on rare occasions amongst stripy drawings the separation weakens when the line is sufficiently thin or when colour is so different that creates a space or in the instances where the work appears as a field rather than grid or stripes. She claimed that her work is about light and lightness which inevitably is in the washes of paint, however, such lightness in the slim aluminium frames starts to be bounded by demarcation of such intention. The most interesting aspects of the work is where aberrations happen in the line.