ALHAMBRA filter transmission curve covering the optical to NIR. From top to bottom, the red curves show the typical redshifted spectrum of a star-forming galaxy at z ~ 1.5, z ~ 1.0 and z ~ 0.5. The gray shaded areas mark the position of the ALHAMBRA filters R₈, I₁₄, and z₂₀, which highlights the position of the Balmer jump. To select the BJG samples, we use the filter directly redward of the gray filter to sample the end position of the Balmer jump.