you can look at any of my ui gauges and see how to do it... Basically there are two ways to do it. I have seen some that have the guage multicolor all the time . The way i did it was the entire guage changes color as health drops. its a long hard process but i feel it was worth it. basically you have to set each guage several times with different colors and offsets so it appears as though the guage is changing colors. let me know which route you wish to go... also sony changed the way gauges are displayed so there is another element added now.