Color representation in Java

Hi everybody!
I am trying to color some lines gradually, depending on one variable, speed, namely if the value of the variable is really small I need a strong color otherwise a more blurry one, even white.
The variable I have is speed so it is varying between 20 and 120 usually.
I tried two ways for doing this but non of them is working :-S All I get is a black color a bit less darker when speed decreases, but u can hardly see the difference.
First try :
float hue = (float) 0.6;
float saturation = (float) (1.0 - speed / 130.0);
float brightness = (float) (1.0 - speed / 130.0);
g2d.setColor(Color.getHSBColor(hue, saturation, brightness));
width = 10;

Second:
g2d.setColor(new Color((float) ((1.0 - speed / 130.0)*(1.0 - speed / 130.0)), (float) (1.0 - speed / 130.0), (float) (1.0 - speed / 130.0)));

I would really appreciate any advice!

I think you have to change only the Saturation


java code

package test;

import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;

import javax.swing.JFrame;

public class HSBColors  extends JFrame{
   
    public HSBColors()
    {
	setTitle("HSBColor Frame");
	setSize(500,500);
	setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
    @Override
    public void paint(Graphics g) {
 
        super.paint(g);
        Graphics2D  graphics2D = (Graphics2D) g;
        float h = 0f ; 
        float s = 0.9f ;
        int b = 1 ; 
        graphics2D.setColor(Color.getHSBColor(h, s, b));
        graphics2D.fillRect(10, 10, 300, 300);
    }
    public static void main(String[] args)
    {
	new HSBColors().setVisible(true);
    }
}