Master Slide

Master slides form the top level of the slide inheritance hierarchy in PowerPoint. A master slide defines common design elements such as backgrounds, logos, and text formatting. Layout slides inherit from master slides, and normal slides inherit from layout slides.

This article demonstrates how to create, modify, and manage master slides using Aspose.Slides for Python via .NET.

Add a Master Slide

This example shows how to create a new master slide by cloning the default one.

def add_master_slide():
    with slides.Presentation() as presentation:

        # Clone the default master slide.
        default_master_slide = presentation.masters[0]
        new_master = presentation.masters.add_clone(default_master_slide)

        presentation.save("master_slide.pptx", slides.export.SaveFormat.PPTX)

💡 Tip 1: Master slides provide a way to apply consistent branding or shared design elements across all slides. Any changes made to the master will automatically reflect on dependent layout and normal slides.

💡 Tip 2: Any shapes or formatting added to a master slide are inherited by layout slides and, in turn, all normal slides using those layouts. The image below illustrates how a text box added on a master slide is automatically rendered on the final slide.

Access a Master Slide

You can access master slides using the Presentation.masters collection. Here’s how to retrieve and work with them:

def access_master_slide():
    with slides.Presentation("master_slide.pptx") as presentation:
        # Access the first master slide.
        first_master_slide = presentation.masters[0]

Remove a Master Slide

Master slides can be removed either by index or by reference.

def remove_master_slide():
    with slides.Presentation("master_slide.pptx") as presentation:

        # Remove by index.
        presentation.masters.remove_at(0)

        # Or remove by reference.
        first_master_slide = presentation.masters[0]
        presentation.masters.remove(first_master_slide)

        presentation.save("master_slide_removed.pptx", slides.export.SaveFormat.PPTX)

Remove Unused Master Slides

Some presentations contain master slides that are not in use. Removing these slides can help reduce file size.

def remove_unused_master_slides():
    with slides.Presentation("master_slide.pptx") as presentation:

        # Remove all unused master slides (even those marked as Preserve).
        presentation.masters.remove_unused(True)

        presentation.save("master_slides_removed.pptx", slides.export.SaveFormat.PPTX)

⚙️ Tip: Use remove_unused(True) to clean up unused master slides and minimize the presentation size.