VMD maintains a database of the colors used for the molecules and the other graphical objects in the display window. The database consists of several color categories; each color category contains a list of names, and each name is assigned a color. The assignment of colors to names can be changed with this window. There are 16 colors, as well as black (the VMD color map), and this window can also be used to modify the definitions of these 17 colors. For more about colors, see the chapter on Coloring.
To see the names associated with a color category, click on the category in the Category browser located on the left side of the window. Click on the name to see the color to which it is mapped. To change the mapping, click on a new color in the browser to the right of the Category browser. For instance, to change the background to white, pick `Display' in the left browser and `Background' in the center one. The right browser will indicate the current color (which is initially black for the background). Scroll through the right browser and select white to change the background.
The Color Definitions tab at the bottom of the Color menu lets you change the RGB definition of the 17 palette colors. Select a color to edit using the browser at the bottom left corner of the menu, then slide the three sliders to set the amount of each red, green and blue component. Default restores the original color definition, and Grayscale toggles whether or not the three sliders will move together as a unit. Color definitions are immediately updated in the graphics window, so you can see the result of your editing right away.
Several of the coloring methods in the graphics window (e.g., Beta, Index, Position) are used to color a range of values, as opposed to a list of names. The actual coloring is determined by the color scale.
The color scale used to assign these colors is set in the Color Scale tab of the color menu. Choose one of the ten color scales from the chooser, and adjust the Offset and Midpoint sliders until the color scale shown at the bottom of the tab is as desired.