How to change the color of a vignette?

So, I am using Post Processing to create a vignette for my game. Now I want to have a speed effect, so when I collect a potion, it turns the vignette green or something. to do this, I use the code:
using UnityEngine;
using System.Collections;
using UnityEngine.Rendering.PostProcessing;

public class ControlPostProcessing : MonoBehaviour
{
    public PostProcessVolume vol;

    public ColorParameter vignetterColor;

    public Vignette vignette;

    void Start()
    {
        vignetterColor.value = new Color(0f, 0f, 0f);

        vol.profile.TryGetSettings(out vignette);
        
    }

    void Update()
    {
        
        vignette.color = vignetterColor;
        if(Input.GetKey(KeyCode.JoystickButton3)) StartCoroutine(SpeedEffect());
    }

    IEnumerator SpeedEffect()
    {
        vignetterColor.value = new Color(0f, 1f, 0f);
        yield return new WaitForSeconds(10);
        vignetterColor.value = new Color(0f, 0f, 0f);
    }
}

This works, or rather in the inspector I see that it changes the vignette’s color. Although, it always disables the color.
While in the scene:
164820-vig.png

while playing:
164821-2vig.png

Ok, I know this is a bit too late. But for anyone looking for the answer like I was doing, you just need to know that for some values in the Volume objcet you will need to override the attribute you are trying to change. Something like this:

private IEnumerator ChangeVignette()
{
    vignette.color.Override(Color.red);
    yield return new WaitForSeconds(0.2f);
    vignette.color.Override(Color.black);
}