I recommend to start from reading of "calibration method " of the colorimeter in question. Rarely, a calibration method of the item is opened in user's guidances. Or in these documents are done normative references to calibration standards/rules/instructions. You save time if you start from reading of user's guidances of items in question. I have a personal experience to find full calibration method (written A-Z) in user's guidances. It is left for me to copy the "text" and put some corrections to adjust the method to my lab pattern.
