The slide master determines the appearance of each new slide in a presentation. It contains placeholders for a title, text, and identifying information like date and slide number. It also stores the standard color schemes. And each of those elements can be resized, repositioned, and formatted.
When a new slide is created, it inherits the appearance of the master. Placeholders are copied to the new slide as determined by the slide layout. Formatting is applied as in the slide master. Any changes to the master are seen in all of the slides based on that master. So the slide master allows you to make "global" changes.
The new slide can then be formatted directly, if necessary. Once a format has been applied to a slide or object on the slide, the formatting that is driven by the equivalent element on the master is overridden, and any future changes to that element on the master will not affect that object or slide. The master thus sets the "rules" and the slide or objects on the slide can be "exceptions."
The slide master does not determine the appearance of slides with the Title Slide layout applied. Those slides are, instead, linked to the title master. All other layouts are driven by the slide master.
To modify the slide master:
- Switch to the master view then click the slide master thumbnail in the left pane of the window.
Once you select the slide master, you can:
- resize, reposition, and format placeholders.
- change the background or color scheme.
- add pictures or other objects.
- change font styles for title, text, and footer elements such as slide number and date.
- do just about anything you would do on a PowerPoint slide.
The placeholders on the master are only for formatting. The text in the master text and title placeholders will not appear on the slide.
When you change the slide master, those changes will appear on all slides based upon that master, unless there has been formatting applied directly to a slide, in which case the slide formatting "wins" and will override the master.
If you want to force the formatting of a master onto a slide, even when elements on that slide have been directly formatted, select a layout in the Slide Layout task pane and choose Reapply Layout from the layout's drop-down menu. If you select multiple slides in the View pane on the left, the master's layout and formatting will be reapplied to all selected slides.