When correctly calibrated, gray value levels of medical images reflect physical properties. In dental X-ray imaging radioopacity of the scanned material is measured through the attenuation of the beam. The measurements are performed with an increasing resolution and bit depth. The human eye though has limited perception capabilities. Therefore, it is not possible for a human being to explore all information represented in the images. Transforming gray value levels as stipulated in the DICOM standard is designed to optimize the representation for human sight. The gray values are altered to transform gray value differences into Just Noticeable Differences (JND) when represented on high quality calibrated medical displays. In this study we explored the eye sight of dental practitioners. A variety of sight patterns detecting gray value differences was observed. Although extremely useful, a transformation such as DICOM cannot optimize the representation for all practitioners, it may even worsen the representation. Transformation of gray value levels should be made dependent on the eyesight of the practitioner.