Producing hard leather in the tanning pits was a lengthy process that took up to two years. Mixing bark and water leached the tannins out of the bark. Hides were stacked and re-stacked several times, ensuring that the tan was evenly absorbed and the process transformed the thick cattle hides into "bark-tanned" leather – which ought to be an even reddish-brown in colour, uniformly strong and still pliable.
Next came the finishing. The pits were opened up, and the wet hides were split in two lengthwise with a scudding knife and then dried. The tanner applied a stiff brush to remove any remaining tan bark and compacted the leather further. In the early days, he’d have used an ordinary hammer. But by the early 20th century, a labour-saving leather roller did the job.
Finally, the hard leather was ready to be sold to shoemakers and other leather trades.
Soft leather was treated differently. It was not layered into the tanning pits after spending time in the tanbark. Instead, a warm mixture of fish oil and beef suet was applied to the flesh side. Thicker types of soft leather then went into the fulling barrel, where the fat mixture was literally massaged into the skins. A skilled tanner then completed the process on the finishing table, smoothing out any wrinkles and unevenness with a burnisher made of stone or iron.
When he’d finished everything to his satisfaction, he nailed the greased skins to poles and spread them out to dry.
Finally, he gave the leather a light additional pounding on the finishing table and removed any subcutaneous tissue residues with what’s known as a whitening blade. Any remaining grease was also removed. The resulting leather was tough enough to be used for thongs.
Very fine leathers went through an extra treatment using hard soap and fish oil. A graining board or pommel made the leather supple, and working it with a glass burnisher made it smooth – and fit to be turned into the finest of leather gloves.
All depictions: © Gemeinde Fricklingen