The commercial protection of ideas, techniques, and designs emerged with industrial capitalism. As a leader in the unfolding intellectual, social, political, and economic revolutions of eighteenth and nineteenth century Europe, Britain had a long history of extending formal protection to ideas and products. A textbook example of early industrial capitalism was the nineteenth century British pottery industry. While the early focus of protection was on technique and product, after 1842, English potters could also register their designs or patterns with the Patent Office and then impress or print the registry designation upon a vessel. Doing so likely served at least two functions. First, it provided the producer with some design protection even though English potters were notorious in their "adaptations" of the patterns of others. Secondly, it served as a positive marketing device to the extent that consumers viewed English pottery as a superior product. However, these two functions were apparently not overly significant because the vast, vast majority of pottery coming out of England lacked registry designation marking. Nonetheless, when a basal sherd displaying a mark is recovered from an archaeological context, we can establish a reasonable dating floor for the vessel.
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. Archaeologists can therefore be provided with a meaningful form of temporal data.
The literature on registry marks and numbers has remained somewhat remote and contradictory. What we hope to provide here is a concise and accurate summary of the codes and dates.
As previously indicated, the marks were impressed (Figure 1), printed (Figures 2 and 3), or, less commonly, embossed. Often times it is difficult to read the small numbers and letters of the impressed forms. If such is the case, we recommend a color scanning at 1200 dpi and then bringing the resulting TIFF image into a program like Photoshop in order to manipulate color. In the Figure 1 illustration all that was done to produce the false color image was an adjustment to gamma. The obscure "3" of the day of the month indicator became immensely more legible as a result.
Figure 1. Impressed early diamond (1842-1867) design registry mark.
Figure 2. Printed early diamond (1842-1867) design registry mark.
Figure 3. Printed late diamond (1868-1883) design registry mark.
Diamond Marks: 1842 to 1883
The following information is adapted from the United Kingdom's National Archives' research guide entitled "Registered Designs: Diamond Marks." The on-line document can be found at:
During the period 1842 to 1883 the British Patent Office issued a diamond mark along with the registration number when a design was registered (see the research guide Registered Designs and Trade Marks for details of registration). The mark identifies the type or class of material (see Table 1 for class codes); the number of items included (referred to as bundles or packages); and the year, month, and day of registration. What follows below is a description of the marks and the information necessary to decode them. Note that the registration number does not form part of the mark. The center is filled by the abbreviation "Rd" which signifies that the item is a formally patented or Registered Design.
The location of the four pieces of information (year, month, day, and number of items in the bundle) contained within the diamond changed in 1868. Take a close look at the illustrations in Figure 4 to observe the changed locations. The year code also changed at this time. In determining the registration date for a particular item, the day will be stamped as an Arabic number, the month code can be found in Table 2, and the year codes can be found in Tables 3, 4, and 5.
Figure 4. The two forms of the design registry mark.
Table 1. Class Codes.
I
Metal
II
Wood
III
Glass
IV
Earthenware
V-XIII
Other Materials
Table 2. Month Codes.
A
December
B
October
C
January
D
September
E
May
G
February
H
April
I
July
K
November
M
June
R
August
W
March
Exceptions:
1. The letter K was used for December 1860
2. The letter G was used from 1 to 6 March 1878.
Table 3. Year Codes, 1842 -1867.
CODE
YEAR
CODE
YEAR
CODE
YEAR
A
1845
J
1854
S
1849
B
1858
K
1857
T
1867
C
1844
L
1856
U
1848
D
1852
M
1859
VEE
1850
E
1855
N
1864
W
1865
F
1847
O
1862
X
1842
G
1863
P
1851
Y
1853
H
1843
Q
1866
Z
1860
I
1846
R
1861
Exceptions:
1. The letter R was used from 1 to 19 September 1857.
Table 4. Year Codes, 1868 -1883.
CODE
YEAR
CODE
YEAR
A
1871
K
1883
C
1870
L
1882
D
1878
P
1877
E
1881
S
1875
F
1873
U
1874
H
1869
VEE
1876
I
1872
X
1868
J
1880
Y
1879
Exceptions:
1. The letter W was used from 1 to 6 March 1878.
Table 5. The Year Codes in chronological order.
YEAR
CODE
YEAR
CODE
YEAR
CODE
YEAR
CODE
1842
X
1853
Y
1864
N
1875
S
1843
H
1854
J
1865
W
1876
VEE
1844
C
1855
E
1866
Q
1877
P
1845
A
1856
L
1867
T
1878
D
1846
I
1857
K
1868
X
1879
Y
1847
F
1858
B
1869
H
1880
J
1848
U
1859
M
1870
C
1881
E
1849
S
1860
Z
1871
A
1882
L
1850
VEE
1861
R
1872
I
1883
K
1851
P
1862
O
1873
F
1852
D
1863
G
1874
U
English Registry Numbers: 1884 to 1995
1. Phoenixmasonry, Inc. maintains an extremely effective and complete site for deciphering English registry marks and numbers. The link is:
3. Steve Birks has created an incredible WEB on the potters of Stoke-on-Trent, England. He identifies and describes the work of over 1500 potters. It is a great site for the identifcation of anything Staffordshire. The link to the registry design page is:
Beginning in 1884, with the initiation of the Copyright of Designs Act of 1883, the diamond mark was replaced by the use of the registered design number printed as a line of script (Figure 5). The simplicity of the technique generally rendered the information more legible. The line of script typically took the form Rd No XXXXXX although Rd XXXXXX is sometimes encountered.
Figure 5. Printed Registry Numbers. By United States law the country of origin was required to be recorded on imported wares beginning in 1891. Consequently, the upper two illustrations are of vessels produced between 1886 and 1890. The bottom two illustrations bear the mark "England" indicating that they post-date 1891.
The number listed for each year in Table 6 is the first registered design number issued by the UK Patent Office that year. The numbers include all material classes, not just earthenwares. To illustrate how to use the table, the ceramic item in the upper left hand corner of Figure 5, displaying Rd No 56790, had its design registered during 1886.
Table 6. English registry numbers for all material classes: 1884 to 1932.
