var color : Color = Color (.3, .4, .6);
print(color.grayscale);

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Color color = new Color(0.3F, 0.4F, 0.6F);
    void Example() {
        print(color.grayscale);
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public color as Color = Color(0.3F, 0.4F, 0.6F)

    def Example():
        print(color.grayscale)