Roger Breton wrote: > I wanted to say that I managed to use argyll in a college classroom setting > today, with success. The students generated, printed and measured a 60 > patches target (I know it's not much but they had to measure one patch at a > time). And they made a profile out of it. Hi Roger, good to hear that you have had some success. > I wonder how I can have them identify the limit of the gamut of this printer > with argyll? There are a couple of ways. One is to visualize the gamut using a VRML viewer. Use iccgamut <http://www.argyllcms.com/doc/iccgamut.html> to create a .wrl file, and then view it. To create a view in L*a*b* of the absolute gamut of a CMYK file with an ink limit of 260%, one might use: iccgamut -w -ff -ia -l260 profile.icm and the resulting files will be profile.gam and profile.wrl. You would need to locate a suitable standalone VRML viewer or browser plugin to view the result. This <http://vrmlworks.crispen.org/get_browser.html> might be a good place to start looking. You can use the viewgam utility <http://www.argyllcms.com/doc/viewgam.html> to compare multiple gamut surfaces and view them. If you want to explore the gamut in more technical detail, then the xicclu utility <http://www.argyllcms.com/doc/xicclu.html> will let you do that. Setup a reverse lookup, and an out of gamut target color will return the annotation [clip], along with the nearest device values. For instance, to explore the absolute gamut of a CMYK profile, 260% ink limit in L*a*b* space: xicclu -fif -ia -pl -l260 -a profile.icm and feed in the Lab values line by line, separated by spaces. If you use the -kv or -kl, then you can also feed black locus or target values in as a fourth parameter. [e.g. xicclu -fif -ia -pl -kl -l260 -a profile.icm and feed in 50 0 0 0 and 50 0 0 1 for the mid grey with minimum and maximum black respectively. 50 0 0 .5 would give you the halfway black point.] Graeme Gill.