1-.Go to File>open, the Registax image.
Make sure it is a RGB image go to >image>mode> click on RGB color.
Optional: go to >Filter>Noise>Despeckle, to reduce noise.
Optional go to Filter>sharper>Unsharp mask amount 100%-50 Radius3.5-1.5 threshold 0
2-.open the Channel window. Window>Show channels.
3-. Find the levels window, Image>adjust>levels
3 & 4-.Click on the blue channel in the channel window (2), to almost reduce its brightness with the levels window(3) move the first arrow to the Right.
5-. Make click on the Channel window to show the green channel and make it darker with the levels window(3).
6-. Increase the contrast from the red doing the same levels adjusts.
7-. Make click on the channel window on RGB and see the results.