An examination of Richard Diebenkorn’s Ocean Park No. 111, 1978, revealed a pattern of lifting cracks that correlated to design and/or color areas. To determine whether or not Diebenkorn’s materials, his working methods or a combination of the two are responsible for the cracking, three additional Ocean Park paintings from the same time period were also examined. One exhibited similar cracking while the other two were in near perfect condition. Materials analysis was completed for all four paintings and the two paintings showing cracking were found to contain an acrylic preparatory layer. The affects of alkyd and oil paint binders on the stability of the paint films was also explored.