Hi, I am trying to use argyllcms for building a color profile. I have a camera which outputs its undocummented proprietary RAW file with linear data. I am happy with the standard sRGB (or AdobeRGB, ProPhotoRGB, etc.) color pictures made by an undocummented proprietary workflow. I would like to study the colorspace of my camera. Now, I have two files for the same picture (not pictures of a chart; just think to a picture of a dog, of flowers or whatever you want): - the RAW file with some linear "RGB" data (PIC1) - the corresponding sRGB (or whatever) TIFF data (PIC2) I found a very interesting thread, which is not too far from what I am trying to do: //www.freelists.org/post/argyllcms/Profiling-between-two-images,7 But the thread was about picture of a chart. What I would like to do is the following thing: with a script, I would like to extract pixels at the same coordinates in both pictures and to have the following columns: column1: Red (unknown color profile) from PIC1 column2: Green (unknown color profile) from PIC1 column3: Blue (unknown color profile) from PIC1 column4: "target" Red (sRGB or whatever known RGB) from PIC2 column5: "target" Green (sRGB or whatever known RGB) from PIC2 column6: "target" Blue (sRGB or whatever known RGB) from PIC2 and I would like my script to write a ti3 (or maybe a cgats data txt file if it is more relevant) without having to care about color charts. Later I will think more concerning the best strategy for selecting 100 or 500 or 1000 pixels (random pixels? selected pixels by some algorithm? etc.) But right now, I want to select say 200 random pixels in PIC2 and call them "target values" and see what are the data in PIC1 for these "target values". But I am very new to this topic, and I couldn't find good examples of TI3 files (or cgats data txt files) on the net. Of course, I could find the following page: http://www.argyllcms.com/doc/ti3_format.html But a short example would be much easier. Could you show to me such a "basic", clean and simple TI3 file (or cgats data txt file) for such a six-column-based set of data? Best regards, T.