This course provides you with a basic working knowledge of color and color calibration. The course concentrates on consistent color and consistent grayscale presentation for the increasingly used color displays in medical imaging replacing the traditional monochrome displays. There will be four main subject areas: • The science of color and color measurements. Here you will learn about the tri-chromatic theory, the color-matching functions, the tristimulus values, the chromaticity coordinates and the various color spaces. Of particular importance for the measurement of color are the colorimeter and the spectro-photometer. • Computational tools for calibration and color reproduction. In this section you will be exposed to a typical system consisting of a colorimeter and a color display with an image for measuring color coordinates of that image, or a color camera for capturing the image of a color display like a color LCD. You learn that you need to do an input calibration, processing and an output calibration. • Assessment of display performance for medical imaging systems. In this section you will be reminded of the AAPM Task Group 18 and its efforts to establish performance criteria recommending minimum performance requirements for safe utilization of electronic monochrome displays in medical applications. You will learn that such efforts will also be required for color displays. • Visual thresholds and the effect of color on the correct diagnosis. In this section you will hear about some of the areas in medical imaging in which the importance of color images and color displays have been explored. Emphasis will be on radiologic imaging, but examples from other areas such as pathology and dermatology where true color images are used will also be referenced. Ultimately the objective of this course is to familiarize you with the elements of consistent color presentation as well as consistent grayscale presentation of medical images on digital color displays for medical image interpretation.