Ti I lines at 2.2 μm as probes of the cooler regions of sunspots H. N. Smitha, J. S. Castellanos Durán, S. K. Solanki and S. K. Tiwari A&A, 653 (2021) A91 Published online: 14 September 2021 DOI: 10.1051/0004-6361/202141447