Breaking down a scene into Layers

We're going to take a look at how an animator goes from a simple sketch to finalized scene in a cartoon. The scene we are observing here is from a project I am working on in my free time called "The Inauguration of Governor Slugwell." This is one of the first scenes in the cartoon where Slugwell goes to give his commencement speech. 

This is a sketch I made of the first scene looking from behind the stage out to the podium.

In animation it is usually best to work from the background to the foreground because of the layering system in Adobe Illustrator (the program I used to color the scene) which allows you to independently build your work piece by piece.

The next closest layer to the foreground would be the audience and seating. You can see how the edges of the layer overlap  parts of the sketched area. This is OK because I can draw over this layer with the next layer.

Here we see the stage layer going into the piece, covering up some of the carpet in the previous layer. Also, I added the podium into the scene.

Here I added the last layer to the background, the curtains. Each wrinkle in the curtain is a different object which I had to draw separately and layer.

Finally I add Slugwell himself as the final layer. The reason I must have this character on a separate layer is because all objects which move in a scene must be able to independently move on its own or when I begin animating the scene whatever is on the same layer will move as he does. It's also just good practice to keep you image organized. This entire scene consists of around 300 objects.