Peeling the Layers – Research on the Evolution of Impermeable Coatings for Leather in Carriages

Prior to the transition of the automobile, coachbuilding reached its peak during the nineteenth century with the many technological innovations and developments that were rapidly being booked – pushing established or emergent companies into making more fashionable and durable carriages than their competitors, be they out of the country or within. Special manual production techniques were kept secret to ensure no other carrosserie company was able to outdo the other. With the turn of the century, however, these close-guarded secrets faded over the next generations. One of them was patent leather; leather that has been rendered waterproof. While recorded in recipes, their credibility is put into question as disclosing misinformation was a common practice to throw off competition.

With special permission, six carriages belonging to the hippomobile collection of the KMKG-MRAH – each originating from a different decade, company, and country – are investigated by combining the study of historical sources (patents and manuals) with a careful optical inspection and chemo-physical characterization to gain insight into this understudied and otherwise unknown material. Research showed that European patent carriage leather is not just oleoresinous, but that the number of coats and and their composition get adjusted to the type of leather and their intended use. Thus, the multifariousness of patent leather deformations is attributed to the fact factories and tanneries had their own japan formulae, therefore the sheer variety in chemical make-ups. It is also suspected that surface deformations are caused if the leather’s expansion coefficient is being impaired.