Mackey's work is primarily about the visual urban experience. She frequently wanders around the semi-industrial parts of her favorite cities - San Francisco, New York and London - sketching and photographing the buildings, piers and warehouses that have been the canvases of engineers, architects, graffiti artists and marketers.

She explores incidents of inadvertent beauty as seen in the collisions of paint, sign writing, posters and graffiti on structures once intended for other uses. She sees the urban wall as an architectural palimpsest recording both the structural and social history of the building and the generations of people it has accommodated.

Mackey's process parallels the visual fragmentation of the urban environment. She works on several wood panels concurrently, building up layers of paint, posters and stencils before combining the panels into a larger piece. The randomly developed under-paintings lend an air of age and decay to paintings of utilitarian structures which are rapidly disappearing under the wave of "urban renewal" rolling over our cities.

Mackey's process, with its fragmentation, spontaneity and acceptance of accident, becomes in itself an extension of the chaotic and colorful urban environment by which it is inspired.