How can you access and change the values of the Vignette and chromatic abberation script progromatically?

I am trying to access the Vignette and chromatic aberration script on my camera, however, when I try to, it gives me this error:

The type or namespace name “VignetteAndChromaticAberration” could not be found. Are you missing a using directive or an assembly reference?

How can I make this script work?

using UnityEngine;
using System.Collections;

public class Choking : MonoBehaviour {

	// Use this for initialization
	void Start () {
	// Update is called once per frame
	void Update () {


Just had this issue myself, add " using UnityStandardAssets.ImageEffects; " at the top of your script and you will be able to reference it.