Left Toolbar > Math Nodes > Rgbo From Numbers
The RGBO From Numbers node allows to set the value of each channel as an input from a Number value. RGBO output: Red Green Blue Opacity.
On the left toolbar choose Point Nodes > Rgbo From Numbers
Drag the Rgbo From Numbers icon into the Node Graph.
Connect the Output .
red A Number type.
green A Number type.
blue A Number type.
opacity A Number type.
rgbo A RGBO type.
These attributes are exposed as input by default. Right-click the Node to hide the attribute as input and set the point values manually. Default R:0.0, G:0.0, B:0.0, O:1.0