In this paper we present a tone mapping operator (TMO) for High Dynamic Range images, inspired by human visual system adaptive mechanisms. The proposed TMO is able to perform color constancy without a priori information about the scene. This is a consequence of its HVS inspiration. In our humble opinion, color constancy is very useful in TMO since we assume that it is preferable to look at an image that reproduces the color sensation rather than an image that follows classic photographic reproduction. Our proposal starts from the analysis of Retinex and ACE algorithms. Then we have extended ACE to HDR images, introducing novel features. These are two non-linear controls: the first control allows the model to find a good trade off between visibility and color distribution modifying the local operator at each pixel-to-pixel comparison while the second modifies the interaction between pixels estimating the local contrast. Solution towards unsupervised parameters tuning are proposed.