The transition from letterpress to digital printing provides the opportunity for a more effective way to communicate information on postal items. Current Postmarks include information such as postage value, date of posting and equipment identification, but this information is not readily machine readable. The emergence of digital printing and image processing technologies offers the opportunity to encode critical data in the form of digital postage marks (DPMs) which are more suitable for computer data capture. However, the adoption of these technologies requires careful study, both to maximise the benefits from their introduction and because digital printing technology might bring with it the need for different security measures than those commonly used in association with letterpress printing. The document identifies a variety of factors which need to be considered in the DPM design process. It has three main purposes. It is intended to serve as: a) a standard process: for the design of applications using digital postage marks; b) a guide: to help in structuring local standards for digital postage marks; c) a cross reference: to point to other standards and documents related to DPM applications. It is stressed that the factors identified are intended to be representative and do not constitute an exhaustive list. Similarly, the document provides many examples of possible architectures and design solutions to the issues which are raised. These are non-normative. They are given for illustrative purposes only and there certainly exists a wide range of other possibilities which are not described. It is not intended to suggest that any one architecture or design or technical solution described is in any way required or in any way superior to any other, whether described herein or not.