During print development, ridge smearing on brushing is a major potential cause of pattern obliteration. It is affected by the quantity and type of fingerprint residue, by the age of the latent fingerprint, and by the number of brush strokes used and the type of brush adapted for print development. Sebum rich prints tend to smear more readily than ordinary prints. The extent of smearing decreases with increasing print age, and magna and blower brushes tend to cause less smearing than the commonly used glass fiber or squirrel hair brushes. Even with prints of a type and age not prone to brush smearing, the prints can be wholly or partially obscured by using excess powder levels on the brush or by excessive numbers of brush passes with normal levels of powder on the brush. 6 figures and 3 references (Author abstract modified)