It is often assumed that the main task of an architectural paint researcher is to identify the original colours employed in an historic building. Whilst this can be established if sufficient evidence survives much much more information can often be obtained.
An examination of the paint layers and their comparison will also show when changes have taken place within a building. Research into the previous occupants may show who was responsible for such work. For example, a recent project on a London house that was built in 1705 has revealed that significant cosmetic alterations were made in the 1820s to bring the house up to date – fashionable chimneypieces were installed; the front door was changed and certain of the rooms were connected by new doorways. Furthermore, it can be seen that the narrow window on the first and second floors were bricked in during the last years of the eighteenth century, while that on the ground floor survived until the 1860s.* The years when the house was occupied by a leading architect of the early twentieth century can be seen in the paint layers as further changes were made – some in an antiquarian style, which had confused the architectural historians.
There are several ways of working out the rough date of a paint layer. Clearly (if complete) one can be reasonably sure of the first and last in the sequence. The constituents often provide clues. The first appearance of Titanium Dioxide in a sequence, for instance, generally marks the 1960s (although notable exceptions have been found). Chrome Yellow, especially when found in the composition of Brunswick Green, tends to suggest the post 1820 period, while the arsenical Emerald Green indicates a date after about 1814.
One advantage of looking at exterior paint is that as paint is applied for its protective, as well as decorative function one finds many more layers. Crudely, having once again established that the sequence is complete, if one divides the age of the building by the number of painted schemes1 a repainting cycle can be established. This will vary depending upon the location, surface and type of building. Typically it will be in the range of four to seven years.
While sampling in the 1705 house a workman brought me a lump of paint that he had prised off the external timber cornice. At first I thought that it was a piece of china, such was the weight and shape. However, it was immediately clear from the traces of the characteristic early eighteenth century red oxide primer at the bottom to the bright white final layers at the top that I was holding three hundred years of the buildings decorative history.
In common with most samples taken from London exteriors two recent events can be seen quite clearly. The first was the years of poor maintenance that mark the Second World War. Weathered paint is visible in the form of volcano-like cracks in the upper layers and this generally indicates the fourteen or so year period brought to an end by the removal of building controls in October 1954. The introduction of the Clean Air Act of 1956 is also evident, for prior to 1956 the surface of each decorative scheme was clearly marked by a layer of airborne soot. From that period on it is often difficult to see where one scheme ends and another begins.
The changing nature of the white component in paint is also clearly reflected in this cross section. Here we can see that White Lead (Pb) was the main constituent until about 1939. Zinc Oxide (ZnO) was employed in the 1950s and a blend of Titanium Dioxide (TiO2) and Zinc Oxide was applied for the rest of that decade, with pure Titanium Dioxide having been used on all subsequent occasions.
The information provided by this cross section also enabled me to establish when the sash windows had been replaced; the elaborate doorcase stripped and (surprisingly) it allowed me to offer rough dates for the last forty years of the interior schemes.
The significance of this sequence only really becomes apparent when one applies a timeline against it.
Taking a number of subsequent random dates we can see how the building was painted in:
1752 – Britain adopts the Gregorian calendar, and we lose the days between the 3rd and 13th of September that year
1830 – The Liverpool and Manchester Railway opens the first intercity rail service between the two cities, under steam power.
1939 – The Second World War begins
It appears that the building was last painted in 2005, the year in which the Provisional IRA issued a statement formally ordering an end to the armed campaign that it had been pursuing since 1969.
In my years as a paint researcher I have never encountered such a complete sequence of decorative schemes. Literally, history in the palm of ones hand.
Acknowledgement: Lucy Inglis
1 This was later borne out by the discovery of a watercolour of the house.
2 A “scheme” is defined as the undercoats and top coat that were applied on each occasion that the exterior was repainted.
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