Comparison between JWST observation of NIR38 background star (top plot) in Chameleon I (McClure et al. 2023) with NIR-Spec FS/395H and the synthetic spectrum (middle plot) obtained with the same column densities derived by the observers, with NIRSpec FS/395H parameters. The stellar spectrum applied is from a K7V star, as it was determined in Dartois et al. (2024) as a good match to the observed photospheric lines. The absolute residuals (observations minus the synthetic spectrum) are given in the bottom plot. The pink rectangles indicate where the grain growth effect is notable in the observation.