In this case, Imageto cannot break the characters apart, because they are a single bounding box. The following options affect individual characters. A negative delta moves the baseline down, a positive one up. This tends to smooth rough edges on characters or irregular curves. By the same token, it tends to shrink or eliminate small features, such as features.
Experimentation is necessary to determine the best values for any particular font.
This process is repeated for every pixel in every character, and every character is filtered passes times. The default is to do no filtering, i.e., passes is zero. In every character, randomly move each black pixel. For each black pixel, a first random number between zero and one is compared to probability . If it is greater, nothing happens.