Hi Maurice,

There's a bit of guidance here:

"New features:

TL-6407 Added a new colours custom setting to graphs in report builder It is now possible to specify graph series colours in the custom settings for a report builder report.

Colours can now be specified using the following syntax in the custom settings input: colours = #ff0000,#00ff00,#0000ff

While it is possible to use any colours the browser supports we strongly recommend only hexadecimal colours are used."

https://totara.community/mod/forum/search.php?search=TL-6407&id=144

The settings should be in PHP ini file format.

Hope this is useful,

regards,

George.