An image forming method of a printing control terminal apparatus which is connected to an image forming apparatus, comprising:
- transforming input printing data into bitmap data;
- storing a plurality of pieces of preset transparency pattern information in a lookup table (LUT);
- comparing the bitmap data with a preset transparency pattern having a plurality of different preset transparency rates to represent various amounts of transparency, and if it is determined that the bitmap data comprises a transparency pattern matching the preset transparency pattern having one of the preset transparency rates, performing smoothing processing with respect to the bitmap data at the one of the preset transparency rates;
- and
- transmitting the bitmap data on which the smoothing processing has been performed to the image forming apparatus,
- wherein the performance of the smoothing processing comprises:
- respectively comparing pattern formats of predetermined pixel areas of the bitmap data with the plurality of pieces of preset transparency pattern information;
- determining whether a corresponding pixel area comprises the transparency pattern matching the preset transparency pattern among the plurality of pieces of preset transparency pattern information, based on the comparison result;
- and
- performing smoothing processing with respect to the corresponding pixel area which has been determined that it comprises the transparency pattern.