R-EX data Discovering the colour history of a room

There are two completely different ways to explore the colour history in a property.

The first way to explore the colour history of a room is a simple ‘rub-back’.

This means to carefully rub away the layers of paint, all the way back to the plaster substrate. This is quick and inexpensive, but it does not provide a definitive outcome. To do this, start with a circle about 20 centimetres across and use sandpaper to gently rub away the surface paint, moving towards the centre as the layers reveal themselves. The result should be a series of concentric circles, each a different colour as the layers of time are revealed back to a small circle of bare plaster in the centre. Switch to a very fine grade of sandpaper as near the end of the process, as this will polish the surface to a fine finish and make the colours as bright as possible.

Things to note:

It is necessary to rub all the way back to the bare plaster, otherwise there won’t be a starting point for the paint history.

Wall were not always painted with the same colour all over. It may be necessary to choose strategic points around the room and repeat the paint rub to confirm how the room was originally decorated.

Warning!  The paints used in Victorian and Georgian times often contained lead. This is toxic and the dust from rubbing should not be inhaled or left on the skin. Wear overalls, gloves and a face mask and, if possible, use a vacuum cleaner to remove the dust as you work. Afterwards, dispose of the protective clothing carefully, or launder fully and do not mix with other items.

When old, lead-painted decoration is first exposed to daylight, it takes a few weeks for them to fade closer to their original values. Also, linseed oil used in old paint darkens over time, causing lighter colours to appear a little darker than they would have been.

The second way to explore the colour history of a room uses micrography.

To do this, a very sharp blade is used to remove a fingernail-sized sample of the paint layers and substrate beneath it. This is then set in resin and, when hardened, the block is cut through the sample and the cut face is polished to reveal the colours. When placed under a microscope and magnified several hundred times it is possible to see the individual layers of paint and even the pigments in each layer that are providing the colours – something not possible with the ‘rub-back’ technique described elsewhere.

Another benefit of using micrography to determine colour history is that it more easily enables the analysis of different parts of a room, including walls, skirtings, architraves and cornice, where small samples can be removed to reveal the history of the decorative finishes. Variations in paint-layer histories may indicate that parts of a room were built at different times, or that materials from elsewhere have been reused. 

Colour Theory

Decorators in Regency times had a small colour palette to choose from, with fewer that 200 pigments. There were also many theories that certain colours had beneficial effects.

For example, the German writer and philosopher Goethe believed that Peach Blossom colours, such as that used in our ground floor dining room, aided digestion and the appreciation of food, which is probably why it is used there.