As far as shapes, the dark oval heads of the firing squad run across the right half of the painting, in an orderly row. The repetition of these shadowy heads indicates the members’ anonymity, and gives a depressing drumbeat of a rhythm to the executions to come. In contrast, the shooting victims’ heads are arranged almost at random. The members of the firing squad are all looking in the same direction; some of the shooting victims are looking down; some are shielding their eyes; and some are looking with fear at the squad. The head of the man in white stands apart, as he looks with resignation at the squad. The painting seems ethereal, without a great deal of mass. The lack of light (except for the spotlight coming from the box) gives this a light, dreamlike feel.
As far as perspective goes, there is some shadowing that gives this a three-dimensional perspective of sorts. However, the emphasis here is on expression rather than realism; the hill and the buildings beyond appear to be flat, as though they comprise a stage or even a painted backdrop to the action in front, giving the painting little sense of texturing, although the characters in the foreground appear to have accurate scale and proportion.. With regard to time, this is a frozen moment, right before the firing of the guns. All motion has paused, as all await the tripping of the hammers.
Most of the colors in this painting are earth tones and grays – the only colors that stand out are the white shirt (symbolizing innocence) of the man standing in the center of the group of shooting victims. The emphasis of the light on the left side gives the painting a decided lack of symmetry, with a tilt to the left: the combination of the light and the lines pushes the viewer’s eyes in that direction. The shadowy firing squad, to the right, is subordinated.
Given its place in art history, this painting is a clear statement against the brutality of war. This is not a glorious gunfight, or hand-to-hand combat; this is the slaughter of innocents by the authority, which has weapons. The sacrificial nature of the slaughter is made apparent by the Christ figure in the center of the victims; the evil nature of the firing squad is suggested by their shadowy cover. If the firing squad were justified, it would not be hidden in darkness: it would feel free to take care of its business in the light of day. Not only is “The Third of May” a shift in the view of war, it also represents a turning point in the morality of combat.