Hello everyone. First things first; Graeme, thanks for making this product. It is invaluable in my opinion. On to buisness. I am quite the newbie in color/luminance/chrominance systems, however I am a quick learner. My focus is to build a library that is usable with TCL. I am only going to start with two devices first(dtp92 and i1disp), but I plan on adding an extra device (the X-rite Chroma 5) to your library (eith augmented i1 driver or another solution..). I have the X-rite DTP94 colorimeter and I need to extract information from readings into another program that does a DICOM (NEMA DICOM ps 3.14) calibration on monitors on different machines running different OS's (Sun Solaris, Apple MacOSX, Linux, SGI IRIX etc. etc.). This program expects luminance in cd/m^2. Seeing that (at least Graeme) some people here know more about the theory and math of colors, if I want to get only the Luminance measurement (nits .. cd/m^2) from the DTP94 (that conforms to CIEXYZ 1931), would it be enough to grab the Y value (from XYZ, seeing that it is supposed to be in nits) and use it to get the nits(cd/m^2)? I am planning on adding the Chroma 5 to the existing database of devices, how did it go with adding the Chroma 4? (maybe it is compatible with Chroma 5) With regards, Sigurður Guðbrandsson