After I have taken my BMP to Ajax model show and had a good look at it, I was not happy with what I have seen. Pigments that I have applied in the end have killed much of the weathering I applied before and whole model looked rather bland. After some thinking Id decided to give the model a second breath of life.
First I have airbrushed model with a thin layer of lacquer thinner coat, this usually tones down the pigments and makes their look more subtle. Next I have used some AK washes and oils to add some life to the model again.
With AK streaking agent I added subtle streaking effects on the rear of the vehicle. These were then accentuated with oils, using Burnt umber color.
After this has dried I added overall mapping with oil colors to add visual richness and depth. I have used few – Sepia, Winsor Yellow deep (these I have liked the best), Indian Red (this proved to be very strong and rich color, so later I omitted it) and Davy’s Grey (this was on the other hand very weak, so I replaced it with Raw Sienna, which was just marginally better). I applied small dots of these paints on the surface and then blended them with moist brush to get more gradual transition between different shades on the surface, while preserving the contrast. It is important to bear in mind that the effect of the oil mapping will be weaker once the paint dries, so you either have to build this in multiple steps or leave the effect during the application one notch stronger than what you want to achieve.
At the end I was much closer to the look I am after, the one of dirty and worn out vehicle operating in a dusty and muddy terrain.
I have in mind few other steps to apply, so hopefully things will at the end go well.
I agree with you pigments dull and kill the effect of depth. I keep them low to just around the running gear. If you could post the before and after pics of your BMP it would help the viewers see what your talking about.