Although his later paintings differ in method from his earlier canvases, the preliminary process remains the same. To create his grid work copies of photos, Close puts a grid on the photo and on the canvas and copies cell by cell. Typically, each square within the grid is filled with roughly executed regions of color (usually consisting of painted rings on a contrasting background) which give the cell a perceived 'average' hue which makes sense from a distance. His first tools for this included an airbrush, rags, razor blade, and an eraser mounted on a power drill. His first picture with this method was "Big Self Portrait", a black and white enlargement of his face to a canvas, made in over four months in 1968, and acquired by the Walker Art Center in 1969. He made seven more black and white portraits during this period. He has been quoted as saying that he used such diluted paint in the airbrush that all eight of the paintings were made with a single tube of Mars Black acrylic.