Kristian Jörg wrote: > Must say that this is a steep learning curve for sure. Why would I need to > measure the display > spectra to calibrate the meter when the goal of my calibration is to > calibrate the display. Seems > like a catch-22 to me... All instruments need calibration against higher standards. Colorimeters do not have perfect standard observer filters (this is the real world), and they will have manufacturing unit to unit variation as well. So by using a spectrometer it's possible to calibrate the colorimeter for your particular displays spectral characteristics. Because the i1d3 ships with it's sepctral sensitivity curves, it's possible to calibrate the i1d3 against a display by simply measuring the displays spectral output (that's what the .edr & .ccss files contain), rather than the particular instrument to display matrix that is all that is possible with other colorimeters. Graeme Gill.