Rule 32(2)(a) sets certain standards for lines and strokes in the drawing, to permit satisfactory reproduction by the various means described in Rule 35(3).

The drawings must be executed in black.

Heliographic prints seldom satisfy the requirements for drawings and it is therefore strongly advised that copies of this type should not be filed.

In all cases the thickness of the lines and strokes must take into account the scale, nature, execution and perfect legibility of the drawing and of the reproductions.

All lines must be drawn with the aid of drafting instruments save those for which no instrument exists, e.g. irregular diagrams and structures.