This study focuses on the visual problem-solving process of clinical pathologists. Its aim is to find expertise-related differences in the temporal arrangement of this process, with a special focus on the orientation phase. A theoretical model of the visual diagnostic process of medical specialists is extended with general problem-solving theory. Participants were 13 experts, 12 intermediates, and 13 novices, who all diagnosed seven microscopic images. Their microscope movements and thinking aloud were recorded. To study temporal arrangement of the process, we applied a time-grid to the data. The results reflected several aspects of general problem-solving theory. Experts and intermediates showed a more extensive orientation phase and more refined schemata than novices. Intermediates also showed a control phase at the end of the diagnostic process. Novices showed a uniform process. These phases were reflected in microscope navigation and thinking aloud, which justifies the extension of the theoretical model.