Chemical sensitization of photothermographic materials based on silver stearate and PVA binder

Cubic AgBr emulsions as a light sensitive component were respectively sensitized by sulfur (S), gold (Au), sulfur-plus-gold (S+Au) or dimethylamine borane (DMAB), and then mixed with other components of PTG materials using PVA as binder. Sensitivity of PTG materials was increased significantly, but with low fog levels. Sodium benzenesulfinate (SBS) could also be used as a new type of chemical sensitizer in PTG materials. The results showed: 1) that the sensitivity of PTG materials could be raised to 30 times than primitive materials when the ratio of SBS mol/AgSt mol is 0.4; 2) that the fog density increased with the amount of SBS; 3) that in the range of 30-50°C sensitization temperature, the sensitivity of PTG materials enhanced with rising temperatures; and 4) reached a maximum at 50°C and in 50 min.