Agnes Martin's Grey Paintings, particularly prominent during the late 1980s, represents a significant evolution in her artistic journey, characterized by a shift towards a more subdued palette that heavily features shades of grey. This series is noted for its introspective quality and minimalistic approach, continuing her exploration of abstraction and the subtle interplay of line and form. The works from this period, such as "Untitled #3" from 1989, demonstrate a deepening of her minimalist aesthetic, featuring thick and thin alternating bars of dark grey tones that evoke a somber mood. These paintings are a departure from the lighter, airier canvases of her earlier phases, presenting a more profound, meditative engagement with color and space (Art Canada Institute) (Art Canada Institute).

During this time, Martin's exploration of grey tones culminated in a body of work that was distinct for its emphasis on a narrower, darker range of colors, which was a notable shift from her earlier, more vibrant works. This period is seen as the height of Martin’s exploration of grey, which she used not just as a color but as a medium to explore the complex interplay between presence and absence, fullness and void. The grey paintings from the late 1980s are particularly significant, as they reflect a critical exploration of emotional depth and continue to engage themes of silence and the sublime, which were central to her work throughout her career (Art Canada Institute) (Art Canada Institute).

These paintings invite a contemplative engagement, where the viewer is encouraged to perceive beyond the immediate visual experience to the nuanced shifts in tone and texture that Martin masterfully creates. This series further solidifies her reputation as an artist who could evoke powerful emotional responses through extremely subtle and reduced means.