This poem examines the tendency of men to objectify women in art and the way that women are shown to suffer as a result. The poem presents us with a male artist who has one beautiful muse who is the subject of all of his paintings. We are told that:
Every canvass means
The same one meaning, neither more nor less.
We can see therefore that in his art the male artist objectifies her and limits her to this "one meaning." The poem becomes more sinister as we see that "He feeds upon her face by day and night," which presents us with an almost vampiric image of how the artist treats this unnamed woman. As the poem ends it is clear that in a sense the artist is not strictly painting the woman before him, because the woman he is painting is:
Not wan with waiting, not with sorrow dim;
Not as she is, but was when hope shone bright;
Not as she is, but as she fills his dream.
Rossetti thus makes a harsh critical comment on the way that women are treated as "art" by men and how as a result they are objectified and used as a "blank canvas" if you will excuse the pun to allow the artist to "fill his dream" rather than being an object in her own right.
In this poem, Christina Rossetti explores a number of key themes. Perhaps the most striking of these is the theme of female objectification. Rossetti demonstrates this through the various female models who appear in this artist's studio. There is the "queen," for example, the "nameless girl" and the "angel." These identities are very limited and one-dimensional and Rossetti does this deliberately. She wants the reader to realize that these identities are a male creation and do not reflect the true range of the female experience.
Similarly, male power is another important theme in this poem and this is shown through the portrayal of the male artist. He is in control of the women he paints, for instance, because he "feeds" upon them and controls how they are appear on the canvas. But, according to Rossetti, the power of this male artist is really an illusion. It is the female figure who is truly powerful because, in spite of the treatment she receives, she is a joyful and happy figure, full of "hope" and optimism for the future.