We have developed a large area, flat panel detector for general applications to digital radiology. This paper presents the x-ray detection characteristics with various semiconductor radiation detectors (HgI2, PbI2, PbO, CdTe) derived by a novel wet coating process for large area deposition. The wet coating process could easily be made from large area films with printing paste mixed with semiconductor and binder material at room temperature. X-ray performance data such as dark current, sensitivity and signal to noise ratio (SNR) were evaluated. The HgI2 semiconductor was shown in much lower dark current than the others, and also has the best sensitivity. In this paper, reactivity and combination characters of semiconductor and binder material that affect electrical and x-ray detection properties would be verified through our experimental results.