In the Printer/Plotter area, in the Name list, select a DWF plotting device. Click Properties.
In the Plotter Configuration Editor, Device and Document Settings tab, expand the Graphics node in the tree window.
Click Vector Graphics.
In the Color Depth area, select a color depth. Click OK.
In the Changes to a Printer Configuration dialog box, do one of the following. Then click OK.
Select Apply Changes for the Current Plot Only to specify a one-time override of the configuration settings that is not saved to the DWF configuration file.
Select Save Changes to the Following File to save the configuration changes to the DWF configuration file.
In the Browse for Plot File dialog box, in the Save In location list, select a plotting location for the DWF file, and click Save. Click OK.