The Ca II triplet is one of the most frequently measured features for deriving stellar metallicities from moderate resolution spectroscopy of red giants in old and metal poor systems. With the advent of 8m class telescopes, this indicator becomes of invaluable help in deriving metallicities for large samples of faint stars in the Local Group, and beyond. Its application to intermediate-age or young and/or metal rich stellar populations, however, is still uncertain, due to the lack of metal rich and intermediate-age calibrators and to the (still unexplored) behavior of this indicator in conditions of varying [Ca/Fe] ratios. In this poster we discuss the extension of the calibration of the Ca II triplet to intermediate-age and young stellar populations and to higher metallicity and present the preliminary results of observing 11 open clusters in December 2002. We also discuss the main objective of this project: to use this revised calibration to estimate the chemical enrichment of the Large Magellanic Cloud and its variation with position in the Cloud.