I am attempting to play an animation in reverse and slow it down, But it only seems to play forwards.

Hello,

I currently have an animation play based on the transform of an GameObject(background). The animation plays when the object is at the correct transform. But what I cannot get it to do it to play the animation in reverse when it reaches the other end. I have seen on other questions that using a negative speed would get it to move in the reverse direction. But this does not seem to be the case, can anyone help me?

Here is the code I have been using.

 using UnityEngine;
 using System.Collections;
 
 public class CameraMenu : MonoBehaviour {
     
     public GameObject background;
     public Transform backgroundpos;
     public Animation MoveLeft;
     public float PlaySpeed = 0.01F;
     
     // Use this for initialization
     void Start () 
     {
         
         backgroundpos = background.transform;
     
     }
     
     // Update is called once per frame
     void Update () 
     {
         if(backgroundpos.position.x == 18)
         {
             
             animation.Play("MoveLeft");
             
             animation["MoveLeft"].speed = PlaySpeed;
              
         }
     
         if(backgroundpos.position.x == -18)
         {
             
             animation.Play("MoveLeft");
             
             animation["MoveLeft"].speed = -PlaySpeed; 
             
         }
     }
 }
 

   

Thank you in advance

Jack Perry