Rd Diamond and Rd No. markings

This is an update to my previous blog post Carron No. 6 sad iron stand. Please review that discussion before proceeding.

Since some UK foundries cast popular designs for many years, would the original Rd Diamond or Rd Number continue to appear on the reverse? Or would, at some point in time, the registration diamond or number disappear? I posed this question to Trivetology readers and received the following response from Dr. Tony Stead of the UK.

My understanding is that there would be no reason to remove the Registration Lozenge from the mould, indeed removal may have required a new, expensive, mould to be created. A new Registration number would only have been issued if the new item differed significantly from a previous item (a bit like a patent). Many items (not just metalwares but glass too) were being made and sold with the Registration Lozenge present well into the 20th century.

Additional information

The following is quoted from An Archaeological Guide to English Registry Marks and Numbers.

Keep in mind that the date of design registration provides only a clue to the year the item was actually produced. Note that we are speaking here only of the applied registry mark and not of the design itself. Given that a design could not be registered if it was produced prior to application submission, the date information tells us only that the vessel bearing the mark was manufactured sometime after the date. If there was a strong enough market, the production runs could be ten to twenty years. However the market was so competitive, dynamic, and creative, and corporate structures and properties so fluid, that products displaying the registration backstamp likely endured for no more than a handful of years. Indeed, the Copyright of Design Act 1842 only extended initial copyright protection for a period of three years. While it remains an important question for further historical research on specific registered designs, I would suggest a generic formula for computing a vessel’s production date. The dating formula is simple: the median of a production range extending six years from the year of registration. Simply stated, employ a production date calculated by adding three years to the registration date. I consider this appropriately conservative. Of course if a production run is historically known to have endured for less or more than six years, then the assigned production date should be accordingly adjusted. While different research questions will beg varying levels of precision, as long as the reader is informed of the date range, its rationale, and the attendant median value employed, one is probably on safe ground.

Utilizing The National Archives for research

The National Archives is the official archive and publisher for the UK government, England and Wales. I plan to follow their Search directions and, by inputing Rd Diamond and Rd Number data, learn more about those trivets in my own collection. If successful, I’ll document my process and what I’ve learned in a future blog post.

Here’s where I’ll start: How to look for records of … Intellectual property: registered designs 1839-1991.

Have you ever successfully utilized The National Archives to research a registered design? If so, I’d appreciate hearing from you. Please post a Comment below or Contact Me. Thank you in advance!