The scale of the drawings and the distinctness of their graphical execution must be such that a photographic reproduction with a linear reduction in size to two-thirds would enable all details to be distinguished without difficulty. In exceptional cases, where required, the scale of the drawing may be graphically represented.[R. 11.13(c); ]
Source: http://www.epo.org/law-practice/legal-texts/html/guidelinespct/e/a_v_7_4.htm
Date retrieved: 17 May 2021