How do I Adjust The Colour Of My Object By Percentages?

Hello, and how are you?

I'm trying (and very, very hard at that!) to change the colour of an object by picking up other objects, what are a certain colour.

For example:

If I was to pick up two red objects and a blue object I would want my object to be 2 parts red and 1 part blue.

Here is the script i'm using.

 var red : float; 
 var green : float; 
 var blue : float; 
 var purple : float;
 var orange : float;
 
 var playerColor : Material;
 
 function Start () {
 
    playerColor = renderer.material;
 
 }
 
 function Update () {
 
    red = red + purple / 2 + orange /3;

    green = green + orange /3;

    blue = blue + purple / 2 + orange /3;
             
    playerColor.SetColor("_Tint", Color(red, green, blue));
 
 }
 
 function OnCollisionEnter (other : Collision) {
 
 if (other.transform.tag == "Particle") {
 
    other.gameObject.SendMessage("SendParticle");
    
    Destroy (other.gameObject);
 
 }
 
 }
 
 function AddBlue () {
 
    blue ++;
 
 }
 
 function AddRed () {
 
    red ++;
 
 }
 
 function AddOrange () {
 
    orange ++;
 
 }
 
 function AddPurple () {
 
    purple ++;
 
 }
 
 function AddGreen () {
 
    green ++;
 
 }

So yeah... It doesn't work. Maybe a tip or two (something...anything..) on how colour works?

Thanks!