Methods to calibrate and display medical images with pixel values with known properties of one or more reference materials provide images which allow more accurate quantification of certain tissue properties. The images provide advantages in medical diagnosis by being standardized and independent of imaging devices or imaging techniques. The images are automatically displayed and/or filmed in optimum windows and levels. The images are calibrated with a variety of reference materials and displayed in a variety of measurement units. For example, CT images are displayed with pixel values in units of grams per cubic centimeter calibrated to a known reference which relate to but are quantitatively different from the customary Hounsfield scale based on water as the reference material. A novel more quantitative CT image display scale provides advantages in diagnosis, image recording and standardization. References with known magnetic properties imaged with MRI provide calibration and display standardization.