In Keynote 6, each Theme comes with a color scheme. I cannot figure out where this color scheme is defined, nor how to change it.
How to change the color scheme?
Or this one from a different template:
See the description at https://monkeydogdesign.com/blog/customize-default-colors-in-keynote, it's tedious but can be done:
Create a custom palette with shades of color:
Don't feel like copy+pasting hex codes? Take a screenshot of the shades, and use the color sampler tool.
You don't have to use shades—you can use any colors you want—this is to illustrate an easy way to create shades like the default colors.
Add and fill a shape:
Drag Current Fill color over default colors:
Note: You can only have one box of each color in the default palettes. If you drag & drop the same color twice, it will simply relocated the block, rather than duplicate it.
Fill shape with next color and repeat:
Replace default gradient fill:
The Color and Image Fill rows will be greyed out when you drag a gradient fill.
Step 6 Replace default image fill:
Like with gradient, the Color and Gradient Fill rows will be greyed out when you drag an image fill.
Where do I find good image fills? Look for textures on a site like pexels.com. Search by color and experiment with adding 'texture' to the search.
By looking at the images you’ve posted it seams that the second palette is obtained by opening a PowerPoint presentation via Keynote: the arrangement of the dark to light shades/tints is opposite and the shades of white-grey-black at the bottom of the palette are quite different.
I assume that you have to create a palette in PowerPoint (the so called Accent colours), save the presentation (it can contain a single blank slide) as .pptx. Then open it with Keynote and save it as .key file.
The original Accent colours (i.e. the last six colours that appear in the first raw of the colour palette in PowerPoint - for example when you want to change the fill colour of some shape) in the Keynote's scheme colours will be placed in the second raw. Now you have a brand new palette to work with. Just check the Master slides in the converted presentation (personally I don’t like the "conversion") and modify them (if necessary).
It's not possible to change this color scheme within Keynote. You can only define the following styles/color schemes: - Form styles - Text styles - Diagram styles - Table styles
The preset color schemes you mentioned are probably "hardcoded" somewhere in the Keynote package files.