Filters are critical to give our model more depth, whereas the weathering phase helps to achieve a more realistic look.
First of all, I sprayed the model with clear gloss acrylic varnish. It helps both to seal and protect the underlying layers of paint, and it let the washes flow better. After 24 hours of drying I thinned some Van Dyck Brown oil paint with turpentine (circa 60% ratio), for a selective wash in the recesses and around the protruding parts. I chose to not make a general wash because, in my opinion, it would have darkened the base color too much.
I waited a couple of days, in order to let the washes dry completely. After that I coated once again the model with satin acrylic varnish (it allows a better control on the filters), waiting further 24 hours. Then I took some oil paints —white, ochre yellow, Naples yellow, green, scarlet red, cobalt blue— and I put a drop of each one on a cardboard, to absorb the oil in excess. I applied small quantities of them with a toothpick making "dots" onto the surface of the model, that I had previously wetted with turpentine.
I used mainly the lighter colors where the base hue was brighter, and the darker ones in the "shadowed" zones. After about ten minutes I blended the dots with the underlying base, using a flat soft clean brush dipped in turpentine, with circular movements on the horizontal surfaces and moving it downwards on the vertical ones.
The overall effect is a "movement" of the base color, that achieves more chromatic variations throughout its shades.
I used Mig pigments —Europe Dust, Light Dust and Concrete— to achieve a dust effect on the model. I applied more powder onto the lower and rear hull and on the wheels and in the recesses. This gives the impression of a tank mildly dusted but still well maintained.
I painted the tracks first with a mix of Track Brown Mig pigment and turpentine, spread onto the metallic zones with a fine paintbrush. Once dried, I faded them with dry pigments —Standard Rust, Ochre Rust and Light Rust, still by Mig— in small quantities, because modern tracks don't rust easily. Finally I rubbed the teeth, that in reality are subject to a continuous wear, with a cotton swab to remove the paint and to bring out the underlying metal.
Finally, I dusted the exhausts with some fine charcoal powder.