This International Standard defines the encoding rules which shall apply to the representation of IPI-IIF image data. The IPI-IIF data format is defined in ISO/IEC 12087-3, called „Image Interchange Facility (IIF)\'. It is Part 3 of the Image Processing and Interchange International Standard, defined in ISO/IEC 12087. The IPI-IIF facilitates the interchange of digital images. It consists of two major parts: the IPI-IIF data format (IIF-DF) definition, whose syntax is described using ASN.1; the IPI-IIF gateway definition, whose functionality is described by an application programmers interface. The IPI-IIF is based on the definition described in Part 1, Common Architecture for Imaging (CAI) of the ISO/IEC 12087. Due to the fact that the syntax of the IIF-DF is expressed using the Abstract Syntax Notation One (ASN.1), defined by ISO/IEC 8824, this standard makes use of the Basic Encoding Rules (BER) for ASN.1, by referring to ISO/IEC 8825 for the definition of encoding rules. NOTE - A rationale for the introduction of new encoding rules in addition to those defined by the BER is given in clause 4. Reference shall be made to this International Standard, and its definitions shall be employed, whenever images are interchanged, according to the IIF-DF, defined in ISO/IEC 12087-3.