I understand exactly what he did up until the point of step 3. After he has basically substituted the the wash for a red-black paint mixture and sprayed it into the recesses where the wash would normally flow, he then misted the tank lightly with a desert sand color. The picture basically shows this this as you can clearly see the recesses have been hit with the red-black and the green on the tank looks a bit yellower. Then all of a sudden in the next picture the tank is completely washed out looking.l know he also used Tamiya "buff", could he have misted the tank with the buff to possibly get this effect?
Here is the tank I;m talking about:
http://www.missing-lynx.com/articles/german/jbpaint/jbpaint.htm