How to declare constant Color

I am trying to declare a constant value which is a color.

Here is what I have done:
public Color color1 = new Color(5/255f, 5/255f, 5/255f);

So that I can access this color in other classes. However, when I try to change this value, for example I change to this:
public Color color1 = new Color(200/255f, 200/255f, 200/255f);

The value Unity uses is still the previous one because I can see the original color appear in the editor. I used to use const for integer but seems I cannot use it for Color.

Thanks for help

using UnityEngine;
using System.Collections;

public class colourScript : MonoBehaviour {

	// Use this for initialization
	Color prvtColor1 = new Color(190f,98f,103f);
	public Color color1 = new Color();

	void Start () {

		color1 = prvtColor1;
	// Update is called once per frame

	void Update () {
		prvtColor1 = color1;

this kinda works, the private variable is taking its value from the public one, but is assigned to the public one at startup. this way you can change the value in inspector to set the private variable. you can take the line out at Start() too to make it so that the public value is independent of the private one.

However, you should DEFINATELY be able to set public values during runtime in your script. just that you cannot change it in your declaration, unless you reload the script.