Object Source Lighting Basics
The technique is pretty basic.
I painted the gauge blue, using the blues used to paint Ultramarines. I also did the highlights on the black areas. Then, I mixed the main blue (the new Ultramarines Blue) and some Black about 25% to 75%, yielding a very dark blue. Thinning the paint a bit with Lahmian Medium, I then blended the dark blue onto where the reflected light would reach the farthest.Adding more and more blue to that, I moved back towards the source (the gauge), finishing with a final edge highlight closest to the source. The very top highlight had a bit of white added to the blue. This was painted on the sharpest edges, closest to the gauge.