Hi Terry. I have asked a very similar question on this mailing list without getting an answer. I was asking not only the “best number of patches” but also the “best kind of patches”: //www.freelists.org/post/argyllcms/targen-for-RGB-printer,1 I am now using a ColorMunki, an i1Pro and many Epson printers in RGB mode (R2400, 4880, 7900). What I can tell you is this: 1) I had the best result using a number of patches between 2000 and 2500 with the following command: targen -v -d2 -G -f2500 -g128 name On the targen page: http://www.argyllcms.com/doc/targen.html you can find a description of every parameter I used. The K3 and HDR inks should be very “stable” (so the behaviour of this printers is very stable over time also if they are not calibrated). I have no experience with less-stable inks so I can’t tell you if I would use a different number of patches. For what I could understand and see in my prints with the Epson printer that I use I have notice no change over time, so I consider that, using the same driver settings, I will get a good “calibration” of the printer (the profile will be good because the printer will behave always in the same way if the driver is properly set). 2) With the ColorMunki you can read the i1Pro patches using a ruler: http://www.youtube.com/watch?v=9PebBQOpP3I in the description of this video that I made you can find information about how to print and read the target. In this way you are going to save paper. 3) To improve your profile you can also “re-read” the defective patches following the procedure that you can find here: //www.freelists.org/post/argyllcms/How-to-improve-an-RGB-printer-profile-using-ti2-and-ti3-files,1 With the –r parameter in chartread http://www.argyllcms.com/doc/chartread.html you can read again the patches that have the worst error in profcheck until you get an average and max error that makes you happy. I could get profiles with max DeltaE 2000 error in profcheck of 0.9. Have a nice day. Vittorio Villani Date: Mon, 21 Feb 2011 16:19:37 -0600 Subject: [argyllcms] Number of patches - well behaved printer? From: t.ritz@xxxxxxxxxxxxx To: argyllcms@xxxxxxxxxxxxx Corpo del messaggio I’m working with a ColorMunki, profiling papers for my new Canon 8300. The 8300 has built in calibration technology and as such, it should be reasonably well behaved. I’m printing on cotton rag matte papers, a fine art baryta gloss paper and canvas. How many patches would you suggest using in my targets? Out of curiosity, how many patches would you use for a less well behaved printer, say an older pigment ink printer? Many thanks. Terry.