Distributions of massive star-forming galaxies in the JWST/NIRCam and TNG100 datasets. Shown are for all galaxy samples the V − J and U − V color distributions (left and center panels, respectively) as well as the absolute V-band magnitudes (right panel). All samples are selected on stellar mass (M_⋆ ≥ 10¹¹ M_⊙). Additionally, we select star-forming galaxies in JWST/NIRCam according to their position in the UVJ diagram (using the cut from Williams et al. 2009). For TNG100, we use an sSFR threshold of 10^−10.6 yr⁻¹ to select star-forming galaxies. We show the results for the simulated galaxies without dust (blue histograms) and with dust (red histograms). While the U − V distributions broadly match, we find that the simulated galaxies are too blue in V − J (by ≈0.9 mag) and too bright in the V-band (by ≈1.6 mag), even when incorporating dust attenuation.