A METHOD OF FORMING A COLOUR GRADUATED PICTURE FROM A BLACK-WHITE GRADUATED PICTURE AND IN PARTICULAR A METHOD OF PRODUCING A COLOUR GRADUATED ISOBAR REPRESENTATION OF A PRESSURE DISTRIBUTION

摘要

A method of forming a colour graduated isobar picture, particularly of the footprint of a pneumatic tire, in which a black-white graduated picture of the pressure distribution is made by loading a tire (16) against an elastomeric membrane (10) having a plurality of shaped projections (12) on one side thereof which contacts a transparent plate (15). A picture of the contact pattern formed by the projections with the plate is photographed. The black-white picture is then placed in iuxtaposition with a heat sensitive liquid crystal sheet which is activated by directing radiant heat onto the liquid crystal sheet throuoh the black-white picture. The image of the activated liquid crystal sheet is recorded preferably by colour photography.