Then I started painting the spikes. First, I applied the base color - Intermediate Blue - and prepared a wash of Smoke.
I applied the wash in order to find all of the imperfections of the miniature, and to apply 'dirt' at the bottom of the spikes. Pulling the brush downwards - to the bottom of the spikes - I brushed them from all sides. This allowed me to achieve smoother transitions on them.
When the wash was dry, I cleaned the spikes and the surface of the shoulder-pads with my base color (Intermediate Blue), where I didn't want any rust.
I chose the direction for light - the same I used when painting the blade of the axe - and I highlighted the shoulder-pads by adding Ghost Grey to the base color.
Highlighting covered some streaks of Smoke, so I thinned it down again and brushed the spikes with it. I also applied shadows onto the NMM on the spherical surface of the shoulder-pad, adding some Smoke to the base color. This is what my mixed colors looked like on my palette:
I mixed some German Uniform, Electric Blue and Dead Flesh. I applied them as streaks on the spikes, but also thinned the mix a lot and washed some parts of the shoulder-pad - this made the colors of the shoulder-pad more coherent with the spikes. I applied some more paint over the streaks, but in a selective way, and with some Ghost Grey.
After checking the photos, I noticed the spikes still lack final highlights, but I'll add them while adding finishing touches to the miniature.