clamp marks

Duplication applying lead in verifying and revealing pressing handwriting has the characteristics of being economical, practical, quick and good in effect.

　压痕字迹是指由于书写运动的压力作用,在衬垫的纸张上留下的无色印压痕迹。

The acting force of prying and pressing marks is leverage effect which is different from that of hitting marks,impact effect.

撬压痕迹与打击痕迹的作用力形式不同,分别是杠杆作用和碰撞作用。