Techniques include receiving a design of an integrated computational element (ICE) including specification of a substrate and multiple layers, their respective target thicknesses and complex refractive indices, complex refractive indices of adjacent layers being different from each other, and a notional ICE fabricated based on the ICE design being related to a characteristic of a sample; forming at least some of the layers of a plurality of ICEs in accordance with the ICE design, where the ICEs' layers are moved along a direction of motion during the forming; measuring characteristics of probe-light that interacts with formed ICEs' layers such that the measured characteristics are spatially-resolved along a first direction orthogonal to the direction of motion; determining, based on the spatially-resolved characteristics, complex refractive indices and thicknesses of the formed ICE layers as a function of the ICEs' location along the first direction; adjusting the forming based on the determinations.