We analyze central surface brightness, nuclear and global colors of intermediate redshift disk galaxies in WFPC2/HST Groth strip and ACS/HST GOODS-N. The aim is to obtain empirical information of relative ages of bulges and disks and to study the relation among surface densities and star formation history of galaxies at 0. 1 < z < 1. 3. We find that 60% of galaxies with bulges define a passive evolution red sequence, while the remaining 40% have bluer colors that may trace star formation activity. We also find that up to z ˜ 0. 8, nuclear and global (U - B) colors strongly correlate with central surface brightness, in the sense that galaxies with brighter nuclei show redder colors, as found in the local Universe. This color-density scaling breaks down at z > 0. 8, where blue colors are found in a fraction of the high-surface brightness nuclei. The associated nuclear star formation must lead to bulge growth inside disks. We argue that blue bulges in 0. 8 < z < 1. 3 may be precursors of local pseudobulges. We do not find evidence for rejuvenation of classical bulges at the sampled z.