Later, when applying the actual camouflage finish to the model, care should be taken to apply the paint in thin coats, ensuring that the underlying shaded areas partially show through and affect the tone of the top colour. The effect of pre-shading can be seen on the side armor of this tank model. Although it may sound tricky for the uninitiated, the whole routine is easily controllable with an airbrush, especially with the top-coat paint diluted to an extra thin consistency. Overall, a straightforward and effective technique. It is recommended to try a darker shade of the camouflage color used, or a very diluted grey.
Some modellers use straight-edge paper masks along the shaded lines to emphasize the effect further.
This might be useful for example on aircraft models to simulate the effects of air flow, or to emphasize sharp division line between adjacent panels. This is a somewhat old but useful technique, popular in the early days when recessed panel lines were new in the industry. The idea is to draw along panel lines with a thin ink pen or pencil. The effect with ink pens can easily be exaggerated. Therefore it is wiser in most situations to use grey rather than black ink to avoid too heavy contrast.