I’ve got a float value of 1 that triggers via a midi note and drives the RGB spectrum equally of a scalar parameter which sends the data to a material (essentially creating a white flash on the object), when the note is released a branch turns the value back to 0. I want the value to fade back to 0 over lets say 1 second and not happen instantly. How can I do this? Lerp + delay didnt work for me, any help is appreciated thank you 
Timeline + lerp will do the trick. Its float track acts as an alpha between the 2 specified values. You can interpolate between the colours directly, too. Read the tooltip of the HSV node for more info:
Thank you, I don’t see how to add the float curve to my timeline node but I’ll figure it out
Double click the timeline, there’s an entire editor inside. Also: Timelines | Unreal Engine Documentation