This study was initiated to provide the ginner with knowledge of the presence or absence of bark (or grass) in the ginned lint during the ginning process. An existing color/trash meter was connected to a PC in a laboratory environment. Simple "run length" algorithms were developed along with variable threshold techniques, to eliminate the effects of variable lighting and to detect bark. The algorithms will detect bark 90% of the time when the piece of bark is at least one inch in length. The programs had difficulty detecting small pieces of bark (0.2 to 0.5 in). As expected, the programs also had problems distinguishing between large leaf trash and bark. The programs are suitable for incorporation into an existing process control system to aid the ginner in his decision making process. However, the programs are probably not accurate enough for use in cotton classing offices.