How to Create a Custom Color Scheme in PowerPoint 2013
(Optional) Repeat Steps 3 through 6 for any other colors you want to change.
The Standard tab of the Colors dialog box shows 127 popular colors, plus white, black, and shades of gray. If you want to use a color that doesn’t appear in the dialog box, click the Custom tab. This step draws forth the custom color controls. From this tab in the dialog box, you can construct any of the 16 million colors that are theoretically possible with PowerPoint.
When you click Save, the new color scheme is saved and ready to use.