Google Slides (Presentations) lacks a transparency setting in combination with a theme colour. Sure, you can set either transparency or theme colour but any combination will be ad hoc. No good. This will help.
There is a lot to OOXML that isn’t available in the user interface of Google Slides (or even MS Powerpoint). Though MS Powerpoint has shading, no need to go under the hood. So, I’ve made this slide in Powerpoint and then converted it to Google slides: #hack slide. It’s got 10 columns rounded rectangle shapes (RoundRect) for every theme colour. The rows are all 10% descending transparency.
These are the steps:
- Copy this slide.
- Import this slide into you Google Presentation project;
- Copy/Paste a shape from the shape library;
- Transform the shape;
- Overlay exact shapes to get colour mixes;
- Change the theme to see the effects.