Bulk samples of red reactively dyed wool were compared to determine whether fiber dissolution and subsequent thin layer chromatography (TLC) would yield additional information to that generated by techniques already used in casework. Several single fibers selected from color pattern cards and casework samples of dye manufacturers were also tested using TLC after their dyes had been successfully extracted. TLC analysis of reactive dyes yielded important additional information, over and above that obtained from techniques such as comparison microscopy and visible light microspectrophotometry. Colored solutions obtained from single fibers were analyzed by TLC and reproducible results were obtained from a range of fiber lengths. 6 references, 1 table, and 4 figures