Hedley Finger wrote: Hi, > My task is simple: to record measurements for each colour paint, and > convert them to colour angle and saturation percentage to plot a colour > wheel with sample spots as shown at the Handprint site. Graeme Gill kindly > pointed me to spotread and xicclu as the commands to use. But I'm totally > bewildered by all the options because I have very little knowledge of > colour science. > > Some questions to be answered: > - Should I calibrate the instrument using the white chip or using the > Arches paper on which the samples will be painted, it being the one I use > for all my paintings? The SpectroLino should be calibrated in the usual way. Since you aren't interested in the L* (or J*) value, I wouldn't worry about normalizing to the media. > - What options should I set for spotread to get the correct output to > the log file? (Graeme has advised me how to edit the log file to retain > just the data needed.) It's pretty much as I laid it out. Just because there are a lot of options, doesn't mean that you have to use them - the general rule is to assume the defaults will do what you want, unless proven otherwise. So literally: spotread log.txt will default to reflective measurement using the Spectrolino, and follow the prompts to calibrate, then measure your colors. log.txt will be a text file. Delete the delete top line and on each line below delete the index number and the next three numbers (the XYZ value), leaving just the 3 last numbers on each line. Locate the lab2lab.icm file (it will be in the 'ref' folder) and use: xicclu -pJ lab2lab.icm < log.txt to compute JCh values. You can of course capture the output using re-direction: xicclu -pJ lab2lab.icm < log.txt > out.txt Note that if you are inexperience in using a command line environment, you will have to come to grips with locating and specifying the file paths, as well as making sure that the ArgyllCMS executables are in your $PATH. A complication on Linux that is noted in the ArgyllCMS installation instructions is the possible need to alter the serial port permissions to allow you to access them. Graeme Gill.