Hallman begins her works with stick figure drawings on paper. The loose and somewhat abstract forms act as a matrix for the composition. She then begins the process of rubbing dry pigment, by hand, into the paper. Between the layers she masks off sections with tape and scrapes away others. She describes the process of removing tape and unmasking areas as being similar to revealing and discovering the nature of the subject. The creative pace is intense; the result is super-saturated hues and curiously crude textures.
Hallman employs symbolic elements in her works, assigning meanings to simple objects. A pea depicts nothingness, while a horse epitomizes freedom. One familiar element in her works is a bird, perched on a shoulder, representing the trusted companion.