In her first blog post on the wonders of Polynomial Textual Mapping (PTM) Dinah Eastop used a modern embossed paper seal as an example of the way in which this new technology can literally highlight and capture virtually invisible details on the surface of three-dimensional objects. So what about earlier wax impressions of seals – would PTM help here?
The National Archives holds probably the largest collection of seals in the country. Seals were used in the medieval and early modern period to authenticate documents as well as literally to seal them. They can include portraits of the owner, coats of arms, depictions of animals or buildings and much more, and most also include writing around the circumference (called the legend) identifying the owner. Many of the seals in The National Archives’ collection are fragile, many are small, and some are damaged, and it can sometimes be very hard to see what the seal depicts.
Traditional photography has often struggled to represent seals adequately, because of the need for light and shade to capture the detail on such small and intricate objects. This is especially true for seals depicting heraldry where even a very small difference on one coat of arms might distinguish it (and the seal owner) from another.
Seals also provide invaluable evidence for the origins of heraldry. In a seminal article published in 1894 the eminent (if occasionally spiky) historian and genealogist, J. H. Round, demonstrated that arms were first introduced into England in the 1130s and 40s. He based his argument on the arms of the great Clare family believing ‘the key to the whole problem’ lay ‘among the Duchy of Lancaster charters, preserved in the Public Record Office’ 1 now The National Archives, namely the seal of Gilbert Earl of Hertford DL 27/47 dating to the 1140s. 2 Round was fortunate. The heraldic chevrons (upside down Vs) of the Clare coat of arms are just about discernable on the earl’s shield depicted in strict profile on his seal. They are however, much more visible using PTM (obviously not available to our great Victorian scholar) and one wonders just how many more early coats of arms await to be discovered and permanently recorded using this new technology. Scholars of dress, armour, architecture, weapons, ships, saints and a host of other favourite seal devices apart from heraldry may well benefit from PTM.
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DL 27/47: The seal of Gilbert Earl of Hertford, dating to the 1140s.
Download the software
For the full experience, including the ability to zoom, you can download the RTI Viewer software, available from culturalheritageimaging.org, then explore the original high-resolution files by right-clicking this link, saving the image to your desktop, and opening it in the RTI Viewer: seal of Gilbert Earl of Hertford (89Mb).
Elizabeth A. New, Seals and Sealing Practices, British Records Association, 2010
SIGILLVM – Seals and Sealing: History, Art, Preservation
The National Archives’ research guide on seals