This paper addresses the issues and challenges encountered in creating a version 4 (v4) ICC profile. After a brief discussion of the major conceptual advancements of the v4 ICC framework over the v2 ICC framework, we describe as a case study the implementation of a v4 sRGB perceptual and colorimetric color-space profile. Although the ICC specification defines a reference medium and reference viewing conditions for the v4 perceptual rendering intent, it does not specifically define a reference medium gamut. Nevertheless one is needed. Within the paper we propose a reference medium gamut, which serves as a fuzzy target for the perceptual color re-rendering. It has been presented to the ICC for further consideration. The discussion of the goals and constraints used for the creation of the perceptual rendering intent should be helpful for the evaluation of the generated v4 sRGB ICC profile and for the creation of future v4 profiles. Visualizations of the perceptual mapping in comparison to the colorimetric mapping and discussions of potential improvements will conclude the paper.