Hi Graeme, Thank you for the detailed explanation. I can appreciate the many contingencies that have to be accounted for and coding for all of them would be almost impossible. I'd like to add that I hope you didn't take my prior message as a criticism...just a question because I don't understand the process. The problem I'm having seems to have been solved...and of course...it's user error! I read a post that said it's not really possible to print the chart in Photoshop CS5 and completely disable colour management. A solution is to use the Adobe Color Print Utility. However, I've found that this utility does not seem to print the chart 1 to 1 but shrinks it a little. I tried other programs and ran into other scaling issues. Printing the EPS in Illustrator or the TIFF in Photoshop, results in no scaling issues. I'm pretty sure that a document without an embedded profile can be printed from Photoshop without color management if no profile is assigned. If I'm wrong...please let me know. Thanks again for a great piece of software, your patience and help! Phil -----Original Message----- From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx] On Behalf Of Graeme Gill Sent: Thursday, August 18, 2011 9:47 PM To: argyllcms@xxxxxxxxxxxxx Subject: [argyllcms] Re: DTP20 (Pulse) patch size error Philip Reed wrote: > I'm wondering why you didn't use the same sizes and configuration as the > charts produced by X-rite software? They have 29 patches per row and each > patch is 6.7 x 12mm. Hi, I followed X-Rite's documentation on creating the charts, and fitted it into Argyll's existing chart printing code. The documentation specifies exactly 6.5mm, which is what the PS and TIFF files contain. My experience was that (for instance) using 6.5 mm patches for the TID did not work, indicating that the documentation needed to be followed precisely, which is what I did. I have no information at the moment on what tolerance the device will handle in this regard, or even if this is the issue at hand. Combine that with (apparently) printers that aren't at 100% scale, and it's hard to know which way to go. Should I add a fudge factor of 0.2 mm, assuming that the device can handle larger but not smaller patches ? If I do, what happens when someone prints the chart on a printer running at 103% scale, and the patches come out at 6.9mm ? Will the instrument read them ? It could be something else, such as the density of the start & stop bits. The documentation says CMY 30/30/30 or 50/50/50, which is a little ambiguous. How critical is it that it be CMY (ie. ink limiting) ? What about RGB printers ? Graeme Gill.