The development of a colorimetric scale as a visual aid for the bruise age determination of bite marks and blunt trauma.

Medical examiners and forensic odontologists are frequently asked to establish the age of a bruise or bitemark on either a living and deceased subjects. The age of bruising has an important medico-legal significance and may be relevant in the investigations related to such crimes as child abuse, domestic violence and homicide. A colorimetric scale for forensic photography based on the colors of the bruise itself, has never been proposed due to the fact that photographic reproduction of color is unreliable and depends on several factors; the camera used, lighting, printer and photo-editing color calibration. The authors propose two colorimetric scales, both with and without linear measurements, and with 90° angulations, six bruise colors, and three circles with black and white calibrators, which are to be used for the forensic photography of injuries involving the epidermis of Caucasian subjects. The two scales could also be employed on living subjects during different stages of the healing process, or on cadavers in order to provide evidential documentation, image verification and analysis. Such an aid would provide a reliable standard condition and allow for color calibration. The colors represented on the scales would be an aid for the interpretation and objectivity required in estimating the age of the bruise, particularly when the analysis is made directly onto computer images prior to printing. The proposed colorimetric scales do not attempt to give a definitive account of the diverse scientific methods available for the assessment of the age of bruising. The observation of a large sample of blunt trauma and bite mark injuries employing the proposed colorimetric scales would be needed in order to verify and validate the use of these scales. It should be borne in mind that bruise age estimation requires an expert opinion with several degrees of accuracy and variability involved. The age of a bruise cannot be determined by color alone.