Figure 3 shows four of the 40 experimental scans. If we put all these 40 scans in sequence, we can form a 3D movie of the sedimentation process. This movie is available as supplementary information. Figure 3.1 shows scan 1 where particles just have been transferred from the reservoir to the sample column. The baseline offset is 0.05 (purple) due to the absorption calculation with an empty cell as reference. We see two main peaks. The peak in the visible region is assigned to β-carotene. In the UV range, there is an overlay of two peaks, one is the UV peak of β-carotene (see Fig. 2) and the other is the UV signal of gelatin. After 15 min of sedimentation, fractionation of the sample is obvious and the first sedimentation fraction proceeds to the bottom of the cell. Scan 10 (15 min) is the last scan where the entire particle range can be seen before the first particles reach the bottom. If we compare the height of the peak in the UV and visible region at different radial positions, the ratio changes. For the faster sedimenting particles, the ratio of β-carotene to gelatin is higher. This is the first important result, demonstrating that the sample is not homogenous. Instead, the particles change their colloidal properties in correlation with the optical properties. The observed effect can be explained by a higher content of stabilizing agent that induces smaller particle sizes. Note that the shape of the peak at 288 nm (Fig. 1) does not exactly match the gelatin absorption and that the expected contribution of gelatin is weak at the applied concentrations, hinting at a combined action of both gelatin and the ascorbylpalmitat added during the co-precipitation in particle synthesis. The third part of Fig. 3 shows the scan after 27 min. Here, the fastest particles have sedimented already. In the fourth part of Fig. 3, we see the last fraction that remained after 60 min of sedimentation, which is mainly composed of gelatin. However, some β-carotene absorption is still visible, which seems to be solubilized in small amount by the excess gelatin or excess ascorbylpalmitat. We do not detect free gelatin in the analysis. In an independent experiment we measured the characteristic sedimentation behavior of gelatin with the interference optics of the Beckman XLI AUC at 44,000 rpm. We found a sedimentation constant distribution from 2 to 10 Sved. This confirms our assignment that the last fraction cannot be pure gelatin.