Double the layer with the soldier's drawing. On the cloned layer we should insert a neutral color, applied with big smears. The upper layer, containing the black-white outlining and Opacity
should be changed on Multiply
. We may easily now add the effect of volume on the layer, containing the colored smears
and not to be afraid to lose the picture. Use a usual brush of circle shape and Flow
. On this stage it's necessary to divide the shape on different surfaces. Merge down those two upper layers.