Four spectra of formaldehyde in natural isotopic abundance in the 3900-4450 cm -1 region were recorded at low temperature at Synchrotron SOLEIL for different pressures. Line positions and intensities were retrieved by non-linear least-squares curve-fitting procedures and analyzed using effective Hamiltonian and ab initio based effective dipole transition moment models. A new measured line list contains positions and intensities for 8929 features. Quantum assignments were made for 5536 new transitions, which represent ~XX% of the integrated line intensity observed in this region. The resulting list of lines is significantly new accurate line positions. All assigned 5536 line positions were fitted to RMS standard deviations of 0.00102 cm -1 . All intensities were received from the predicted value from ab initio variational calculations reported