If you have multiple Slide masters, you need to change them individually. The image below shows how I was able to apply two different themes to each slide master. Preserve Slide Master. In the end ...

With editable master slides, you can now easily tailor how content appears on every slide by selecting “Edit master” from the Slide menu. For example, ...

When you edit the slide master, it will impact all other slides. If you edit the layout slides, it will only impact that one particular type of layout. We recommend that you that you edit the master ...

It's the view where you can set elements of design that appear throughout your presentation, such as the slide background and foreground colors, any reoccurring elements, and the fonts. By creating ...