The design of a color facsimile machine presentsa number of unique challenges. From the technical side it requiresa very efficient, seamless integration of algorithms and architecturesin image scanning, compression, color processing, communications,and printing. From the standardization side, it requires thatagreements on the color representation space, negotiation protocols,and coding methods must be reached through a formal internationalstandardization process. This report describes our experiencewith the development of a prototype color facsimile machine, withemphasis on the image processing aspects. The prototype has beendeveloped to provide a test-bed while the standard is being negotiatedand to recognize at an early stage the challenges for commercialdevelopment of color facsimile machines.