c i pigment yellow 147 and of c i pigment red 177 for this purpose 20 mg of the corresponding pigment was dissolved in 98 weight d 2 so 4 just before measuring the solution was inserted into a ceramic spinner and the spinner was inserted into an nmr apparatus bruker advance iii 400 mhz nmr spectrometer set at 80 u00b0 c 1 h nmr spectra were measured in time intervals of 5 minutes fig1 shows the obtained 1 h nmr spectra of c i pigment yellow 147 after 5 minutes and after 1 hour fig1 also shows the formula of c i pigment yellow 147 together with figures ranging from 1 to 4 and 8 to 13 which mark the positions of carbon hydrogen bonds in the pigment wherein the hydrogen atom h not shown in fig1 could be substituted by a sulfonic acid group so 3 h the 1 h nmr peaks originated by said h atoms are also identified in the obtained spectra fig1 shows that the peaks of all of the h atoms after 1 hour in the 80 u00b0 c d 2 so 4 are completely identical with the peaks after 5 minutes so surprisingly not any sulfonation occurred in c i pigment yellow 147 fig2 shows the obtained 1 h nmr spectra of c i pigment red 177 after 5 minutes and after 2 hours fig2 also shows the formula of c i pigment red 177 together with figures ranging from 1 to 6 which mark the positions of carbon hydrogen bonds in the pigment wherein.