It is not easy to give a distinctive performance of Bach’s suites for solo cello, something that makes those familiar pieces sound new. That is what baroque cellist Tanya Tomkins did Saturday afternoon in an insightful traversal of all of six suites over two concerts closing out the Library of Congress’s Bach festival. Tomkins, who had to cancel these concerts last season because of illness, came close to doing so again because of an allergy set off by the odor of painting in the building.

As she explained between suites, Tomkins played on a historical instrument fitted to 18th-century standards: higher strings made of gut, lower strings made of gut wrapped with metal, lower string tension (and tuning at A415), a lighter bow that danced across the strings. Specialization in baroque music, from her work as principal cellist in the Philharmonia Baroque Orchestra, Portland Baroque Orchestra and other ensembles, helped her interpret the cues in the score about interpretation. The preludes had an improvisatory character in cadenza-like sections, and the dances lilted with the sense of movement. The allemandes were noble and genteel, the courantes rippling and fleet, the sarabandes graceful but not too slow and the gigues a little rough and folksy.

The greater resonance of the instrument’s strings allowed Tomkins to take more double-stops in strict meter than generally heard on modern instruments, as in the crisply delineated fugue introducing the fifth suite, which was performed in the scordatura tuning indicated in the manuscript. Only the sixth suite disappointed slightly, not because it was performed on the sort of smaller, five-stringed cello for which it was probably intended, but because Tomkins did not have enough time rehearsing on this specially loaned instrument to control its somewhat unruly sound, especially on the highest string.

Downey is a freelance writer.