Table 2: Comparison of codes determined for caffeine and cocaine by both visual and digital color image analysis. Visual codes were determined by 5 interpreters while digital codes were obtained using an in-house designed macro for use in Image J to measure changes in RGB values. The hyphenated code is assembled beginning with DC1 in buffer A–DC1 in buffer B–DC2 in buffer A–etc. N represents the number of total codes determined and the percentage error represents the total deviations from any of the 16 digits of this determined code.