Under drying, drops of concentrated silica sol deposited onto flat substrate undergo large morphological changes. We have performed accurate measurements of the drop profile during the solvent loss. The results obtained for different drop volumes have been interpreted using a renormalization procedure. The length and time scales agree well with that expected when the evaporation is limited by solvent diffusion in air. The final thickness of the solid film deposited onto the substrate is compared with a simplified model of drop drying.