shaping and design : Crash course : The optical mid							top
			When is a text put exactly in the mid of a page? Of course, when the spaces above and under it are equal. But the picture on the left shows that with this arrangement the text seems to be placed too deep.				So we have here an optical illusion. In this example I pushed the text (nearly too much) higher. So it lies far above the mid. Nevertheless it seems to ly in the mid of the page.		Among experts this phenomenon is called optical mid. It lies always a little above the real (mathematical) mid. That is why the lower margin is always larger than the upper one.		Also in table-setting, in shaping visiting cards, even in other fields of design like photography it is relevant.