Looking at Theodore Gericault's work The Raft of Medusa, one may notice the artist's use of color as contrast to show the moment of transition from despair to hope.  The darkness of the clouds and of the sea contrast with that of the horizon, the emotions across the characters faces, and the emphasis on certain figures within the painting all help contribute to that overall theme. 

The dark clouds and seas both have a brown base with varying shades of dark greens mixed within to help provide contrast against the light yellow of the light coming from the horizon.  If the clouds or sea had been painted with shades of blue instead of green it would have pulled the viewers eyes away from the subjects and thus taken away from the image itself instead of keeping the image grotesque by the muted color palette.  The murky browns and greens allow the lightly colored, pale flesh of those on the raft to stand out and draw the viewer's eye in.  Dark coloring more often than not has a negative and mysterious connotation.  That is why the dark clouds and sea are perfect examples of the despair the sailors on the raft are or were experiencing.  The waves are washing up on the poorly crafted raft to take away the dead and pull their bodies down into the depths of the ocean and the unknown.  The ominous black clouds in the sky are broken by the light horizon.  If one looks closely, they can see a small speck in the distance that appears to be another ship.  While the darkness of the clouds represents all that has been lost and the gloom of the current predicament of the people on the makeshift raft.  That tiny speck is their last promise of redemption from the horrific scene that is presented in the painting. 

The painting draws the viewer's eyes up toward the figure waving the flag to help demonstrate the change from despair to hopefulness.  At first glance at the painting, one's eyes are drawn to the figures in the lower left-hand corner because of the light colors the artist uses for their bodies.  Several bodies are strewn across the bottom of the painting help illustrate the gloomy situation all of the other characters in the painting are in.  An older gentleman is holding a dead man in his arms with a look of anguish.  One's eyes then travel up in a curve in the same direction as the faces and outstretched arms of the others on the raft.  The expressions on the faces of the people along this upwards curve starts to become one of optimism.  This puts major emphasis on the character eagerly waving the red and white flag.  Another contributing factor to the emphasis placed of the flag-waver, is the height of the sail on the raft.  Typically, one would not think of a makeshift raft to have a sail on it but the addition of the sail in the painting helps add to the overall composition and balance of the painting.  Because the sail is dark compared to the bright coloring of the person waving the flag, it helps draw the eye to the only other figure of that height.  

If one were to look closely at the painting, The Raft of Medusa, they would notice that there seem to be two triangles within the painting itself.  Not actual triangles, but the way the artist groups the different subjects within the painting give the illusion that there are triangles within the piece.  Each of the triangles represents something different, one hope and the other despair.  Starting at the bottom left again with the few dead bodies and the old man holding the younger dead one, one is able to see the pain and the suffering that these men endured.  Beside the older gentleman is another figure, often skipped over by the eye because of the dark colors the artist chose to paint him in.  He too appears to be looking into the distance at the speck along the horizon line.  However, he isn't bothering to frantically wave for the ships attention.  If one looks even closer, they'll notice someone behind the old man.  This particular gentleman is grabbing and pulling at his hair.  He also seems to go unnoticed, like the person beside the old man and the few huddles up next to the sail, because of the darker hues and colors they are painted in.  It relates back to how darkness is often associated with something negative or depressing.  Most of the figures in the left triangle have very clear expressions of anguish or are painted with darker colors to give off the impression of gloom.  Now if one were to look to the right side of the painting they would see the triangle of hope.  Each of the figures in the right triangles are reaching out or waving flags desperate to capture the attention of the small speck in the distance to come and rescue them from their raft.  The people in this triangle are also painted with much lighter colors to illuminate their sanguineness of rescue.  

Theodore Gericault's use of contrasting colors throughout his work The Raft of Medusa to help emphasize the shift from despair to hope.  He illustrated that theme through the contrast of the light horizon against the darkness of the clouds and sky.  He also placed an emphasis on the top right figure waving the red and white flag as a symbol of hope for the people aboard the raft.  The last way the artist exemplifies the transition is through the two triangles.  All together, they create a progression from sorrow and darkness to one of optimism and promise. 
