Setpixels leads to a blank texture?

Hello!

I am trying to multiply two textures together and output the result on to a plane for testing purposes. The textures are read/write enabled. The issue is that although I receive no errors in the console the output texture is always blank. I have tried to just get the pixels from one of the input textures and then set them to the output without altering them in any way but I still end up with the same error.

Code posted below;

 using UnityEngine;
 using System.Collections;
 
 public class TextureBlend : MonoBehaviour {
 
     public Texture2D noise1;
     public Texture2D noise2;
     public GameObject target_Object;
 
     Color[] _noise_Array1;
     Color[] _noise_Array2;
     Color[] _output_Array;
 
     Texture2D output_Texture;
 
     // Use this for initialization
     void Start () {
 
         output_Texture = new Texture2D (256, 256);
 
         _noise_Array1 = noise1.GetPixels();
         _noise_Array2 = noise2.GetPixels();
 
         for (int i = 0; i < (256*256); i++) {
             _noise_Array1[i] *= _noise_Array2[i];
             }
 
         _output_Array = _noise_Array1;
 
         output_Texture.SetPixels (_output_Array);
         target_Object.renderer.material.mainTexture = output_Texture;
     
     }
 }

Any ideas?