Same answer as this question : How can custom colouring be set up in Sense ?
You can only change some colors (i.e. bargraph bars colors) using colors "by expression" and use rgb() or argb() functions.
Did you try with an equal sign befor : =rgb(...) ?
As exemple, you can try to put some data in script :
LOAD * INLINE [
Product, R, G, B
Car, 255, 0, 0
Boat, 0, 255, 0
Truck, 0, 0, 255
then create a bar chart with any expression (i;e. RowNo() ) and expression color as =rgb(max(R),max(G),max(B))
As your problem seems like maintain all your custom coloring from one place. You have 2 options.
Use color by expression to color it the way you need.
1) make use of environment variables: this will actually help you in the case of re usability or easy color governance
2) Have a database table or a file which contains these color codes and make use of them dynamically.
Hope this helps!
- Sangram Reddy