 <p>Here the script version!</p> <pre><code> using UnityEngine; using System.Collections; using UnityEngine.UI; public class SetTransparancy : MonoBehaviour { public Button myButton; // Use this for initialization void Start () { myButton.image.color = new Color(255f,0f,0f,.5f); } // Update is called once per frame void Update () { } } </code></pre> <p>I tested it in Unity5</p>