Throughout much of the poem Blake’s language is dark and the colors of the second set go along with that better. The first set uses cool, relaxing colors, but the second has more warm, energetic colors. Blake discusses villains, “the vale of death,” a “sneaking serpent,” and also gives a very dark description of the “Printing house in hell.” While reading these parts it seems that the second set of plates are more appropriate for the poem. The reds, browns, and oranges go along very well with a description of Hell.
The first set of plates seems to be more appropriate for the part of the poem that relates to the soul. When Blake describes the difference between good and evil he says that good comes from the soul. He talks about evil being something that is not necessarily a part of oneself, but that is something you can control. Reading this while looking at the first set of plates makes it seem somewhat more optimistic. Maybe he is trying to say that people can control their evil desires, because to someone that is spiritual the soul is stronger than the body.