This kind of material besmears only in one side , this material rises autotype action .

这种材料只涂在一面，这层材料就起复写作用。

The supermarket controls silver bar appearance one also besmears have this kind of stuff , can engrave a black shadow to come with good thing so , wait to be in then autotype .

超市收银条表面一层也涂有这种材料，所以可以用硬物刻出黑影来，就等于是在复写。