Create a Text Master
The Text Master is different from the Title
Master, in the same way that the cover of a book or magazine is
different from the content.
6. Design a Text Master
Go to View ->Slide Master.
Select the Text Master from the list.
Go to Background Styles.
Select: Format Background.

Click on Picture or texture fill.
Choose Insert from File...
Edit the Offsets:
Left: -10%
Right: 30%
Top: 10%
Bottom: 10%
Change the Transparency to 65%