How to store and reuse RGB var

I do use a RGB LED light controlled by the command “rgb_color”: [255,0,0] (for example)
How to store such a value into a variable? and/or reuse it later in a light state function in nodeRED?
I tried severall solutions, non are working.
I tried to store [255,0,0] as a string for example

I did found the answer myself:
to store the RGB value:
to set in call service node:

{ "brightness_pct": "75", "rgb_color": [{{global.LedKleur}}]}