There is a great number of forensic applications in which it is useful to compare black inks of inkjet printings, for example anonymous letters. Usually, forensic document examiners study dyes of inkjet printings using Raman spectrometry, Thin Layer Chromatography or High Performance Liquid Chromatography. These methods are ineffective when the examiner must study a pigmented ink. Most of black pigmented inkjet inks are based on carbon black.Using our protocol, PY/GC/MS allows to study the solvents of an inkjet printing. For different inks, we find different solvents in different proportions. Thus, we have found 2-pyrrolidinone, glycerin… For this study, we have used 16 printings coming from 16 different inkjet cartridges (11 inks based on pigment, 5 inks based on dyes) and we have finally identified 13 different groups.