Epson GT-6500 EN - Manual (Page 141)

Each halftoning mode has the following characteristics.
Halftoning mode A (hard tone)
The image is processed to produce hard tones, to express distinction.
This mode is suitable for most purposes.
Halftoning mode B (soft tone)
The image is processed to give soft tones. This mode is suitable for
images that contain large areas of similar tones.
Command Reference 3-47