How does Eamon Grennan use imagery in Station?

The poem has many contrasts between light and dark. These contrasts suggest the mixed feelings the father has about his son's departure. Light is first suggested by the phrase "platinum dazzle" and the phrase "he's entering into the light / of the world." This imagery continues when the father feels the first growth of down on the boy's face, which he knows he can see "when the light is right." He refers to it as the boy's "next life / in bright first touches."