Introduction The value of fine grids, electromarked (1) on to metal sheets before pressing, so that the type and magnitude of the strain developed in the critical region of the pressing can be assessed, is undisputed. Keeler (2), Meyer and Newby (3), and Goodwin (4), have all discussed practical applications of this technique and Palmer (5) has reviewed the field and introduced the concept of a relative safety factor (MSF). However it may be useful to see what this 'mark' consists of, how the marking affects the subsequent metal performance, what the limitations of the process are and other peripherical issues. It is these aspects of the process which is the concern of this paper.