Signal level can vary based on a number of factors. The amount of iron oxide (concentration) that is present in the character will affect the signal level. This is a function not only of the toner itself, but also of how it is laid on the paper and the pile height which can be controlled by numerous other cartridge components (i.e. "hot" OPC's).

The taller the vertical edge of the character, the taller the peak (either positive or negative). If the vertical edge is not regular, and/or not vertical, this will result in a reduction in the amplitude of the peak and will flatten the peak out.

Keys to proper waveform detection are:

• All peaks in a character's waveform must be detected. The reader sorter must know that the peak is there.
• The peak must be located at or near its anticipated location.
• No significant "extra" peaks can be present.
• There cannot be wide variations in the signal levels of peaks within a character.