The armband is made of brass and therefore needs to show more oxidation. I am still building up color and here is how I will proceed:
To paint brass objects, there are various way of color choices. For example, you could use Burnt Umber and Cadmium Yellow Light to get the main color of the object. For the shadows a bit of Alizarin Crimson and Black will do the trick. Highlights could be achieved with Cadmium Yellow light and White.
Since I try to limit my use of Cadmiums, I get the same colors by mixing Raw Umber and Yellow Ochre Light into various values. White is added for the lightest values of that yellow string. Highlights are done in the lightest Yellow value plus White.
To get the shadows richer I add Alizarin Crimson, it is a transparent hue and rather than alternating the color, just adds a nice glow when used as a wash over the Umber.
Remember to have lost and found edges. To add a sense of turning of the armband watch how the light will change direction and how things become more muted and with less definition as they turn into the shadows and further away.
The result of this new layer will be posted later.