Greetings, A few months ago I created a “No K” profile by doing just what Liane suggested and we are presently using it on our HP Indigo. Except for dark colors is is hard to tell the difference on the printed pieces between using the 4 color and the 3 color profile workflow. FYI - I did a bit of experimentation yesterday and tried to make a 4 color profile by first deleting the K channel from the reference file - received error while profile was being made. I then tried leaving the K channel in and made all K values zero - once again received error. Took the time to replace any value in the K channel with a 1% and was able to build a profile from the measurement file without error. So as Terry said it appears that iProfiler needs some values in the K channel. I have, in Photoshop, used both my 4 color and 3 color profile to convert an RGB test target and both seem to produce values very close to the original RGB lab values - with only the darker colors taking a bit of a hit. -Bill-