"Then I will try again," said George, in a decided tone; and, flinging aside his half-made kite, he turned and re-entered the house, and was soon bending in earnest attention over his lesson.
Bump exposure: Method of increasing highlight contrast when producing a half-tone by removing the screen briefly to remove any dots in the highlight area.
无网曝光：是增加半色调图片的光部对比的方法。摄制时把网片除下作短时间曝光使光部的网点消失。
3
Zinco a line or coarse screen half-tone block etched on zinc for letterpress printing. see zinc engraving.