Optical emission spectroscopy and Langmuir probe measurements have been performed under varyingconditions, close to those previously optimized for high-pressure on-axis DC sputter deposition ofY Ba2Cu3O7−x (Y123) films. The electron temperature and density of the plasma weremapped between the target and substrate. The aim of the investigation was todiscern the effect of small variations of plasma environment on film growthand thus to enable precise tuning of the deposition conditions for Y123 andY Ba2Cu4O8 (Y124) films for different applications. The input parameters varied were:Ar-to-O2 ratio in the sputtering gas and small additions of He,H2 orH2O; total pressure; target composition (Y123 or Y124); and deposition temperatureTs. The films were characterized by four-point and inductiveTc measurements, x-ray diffractometry, Raman spectroscopy, Auger electronspectroscopy, Rutherford back scattering, x-ray photoelectron spectroscopy, atomicforce microscopy, scanning electron microscopy, and x-ray energy dispersivespectrometry. A model has been developed to account for the structural peculiaritiesobserved in the x-ray diffractograms of hydrogen-loaded Y123 films deposited inO2/Ar+H2O presented.