The dataset contains a downcore color scan of Kasten Core M144 KC5-6 for each 1cm. The analysis was performed onboard the R/V Meteor using a A MINOLTA CM-700d hand-held spectrophotometer combined with a CM-A178 target mask (Ø 8 mm, with plate). Color data were reported in the CIELAB space using the Lab system. To calibrate the spectrophotometer, a Konica Minolta White Calibration Cap CM-A177 and Zero Calibration Box CM-A182 were used. Spectral reflectance was measured over a wavelength spectrum from 400 to 700 nm. Low L and a* values representing darker, organic rich layers were defined sapropel phases as discussed in Pallacks et al. (in review).