Each spiral arm exhibits [a]{} similar overall shape [in]{} the IFS and IRDIS images. As the position angle increases (i.e., going closer to the star), the IFS profile for S1 shows [alternating]{} maxima and minima. [The peak-to-peak variations are $\sim$25–40 mas]{}. The IFS profile for S2 has a constant width of $\sim$60 mas in its external part then exhibits a slightly increasing slope for position angles larger than $\sim$140$^{\circ}$. We note some [local differences in the IRDIS profiles with respect to the IFS data that can be attributed to a poorer spatial resolution or sensitivity effects]{} (shallower minima depths).

[Figure]{} \[fig:spiralpeak\] shows the surface brightness profiles along the spiral spines for the IFS and IRDIS bands. [We retrieve the]{} increasing trend of the disk surface brightness with the wavelength seen for the radial surface brightness profiles (Fig. \[fig:brightnessprof\]), especially for the IFS bands.

Finally, we extracted from the deprojected and $r^2$-scaled RDI images the reflectance spectra integrated [on the S1 bright blob feature, the S1 regions outside its blob feature, and S2]{}. Figure \[fig:reflectancespectrum\] shows the spectra normalized to the [stellar spectrum measured in the unsaturated non-coronagraphic data]{}. The error bars on the measurements account for the errors in the 