Painting yellow armor (for whom who don't have an airbrush like me)

When painting the Marines Malevolent, I encountered a small problem: the way I paint usually was not suitable for painting yellow armor. Usually I go from dark to light through a lot of layers, but in this case it gave a sad result, since yellow is very difficult to work with. I tried to go from light to dark, but it gave too little depth and color saturation.

In the end, I decided on the method used by a fairly large number of painters: I did a contrasting underpainting and then painted on it.
So, at first, I covered the black undercoat with a layer of Khaki (Vallejo Game Color) [Fig. 1] and then made base mixes for underpainting. For this purpose I used Brown, Dark Tangerine and Yellow from Pacific88 Art-Color.

I divided these mixtures into three parts: for shades the mix of brown + dark tangerine, for lights - dark tangerine + yellow, and something mean for the middle. With the help of these mixtures I made the underpainting [Fig. 2]

The next task was to make the transitions smoother. I started with light areas. For this, I first made a few glazes with a mixture of yellow and dark tangerine made several openings on the borders of the underpainting to blur them. After that, I used pure yellow to brighten the lightest areas, and finally all those openings blurred the boundaries remaining after the highlighting [Fig. 3]

Then I started to use shadows in a similar manner, only using brown and dark tangerine with different proportions for glazing. [Fig. 4]

After smooth transitions, I needed to increase the contrast. To do this, I first made extreme highlights with a mixture of yellow and pearl white (Pacific88 Art-Color), after which I made them glazed by clear yellow, so as not to lose color. And, finally, once again, a mixture of yellow and pearly white, but thinner and more accurate [Fig. 5]

And, finally, I drew additional details of black and battle damage by the brown and a mixture of yellow and pearly white [Fig. 6]

For reference, a color track and used colors are attached. And as bonus for whom who don't have a P88 paints: the alternative variant with more common paints used. It do a little less color depth but looks very similar.