WASP-121b NIRISS SOSS eclipse chemical equilibrium retrieval results overview with (green) and without (dark blue) fitting for an albedo. Top left: retrieved day-side vertical temperature structure (1 and 2 σ contours) compared to the median TP profile inferred from NIRSpec G395H observations (Evans-Soma et al. 2025, dashed black line). While the temperature is generally above the VO (dashed dotted light grey line) and TiO₂ (dotted dark grey line) condensation curves (Burrows & Sharp 1999) on the day-side, the colder night-side may allow for some titanium condensation. Top right: measured day-side brightness temperature of WASP-121b (black points) compared to the best fit atmospheric model from the chemical equilibrium retrieval with A_g fitted (solid green line). Opacity contribution from individual species and reflected light are shown in colour. Compared to when assuming A_g = 0 (Fig. 5, top-right panel), TiO is no longer necessary to match the data at shorter wavelengths when reflected light is considered. Bottom: from left to right, the log volatile metallicity, log refractory metallicity, log titanium metallicity, carbon-to-oxygen ratio, geometric albedo, and hotspot area scaling factor. Shown error bars are either 1 σ bounds or 3 σ upper limits. While [𝒱/H] and [ℛ/H] are always above the stellar (orange dashed line) and solar (turquoise dashed line) values, the inference of [Ti/H], the C/O ratio, and A_HS depends on whether or not A_g is fitted. In particular, the model either needs reflected light and an albedo of $A_g={0.16}_{-0.02}^{+0.02}$, or the combination of TiO and a slightly stronger temperature inversion to fit the spectrum. However, in both cases [Ti/H] is underabundant compared to other, less refractory metals.