Acrylic paint on vellumed paper
The Shell pattern was introduced in the late eighteenth or early nineteenth century. It is basically a Turkish Spot pattern where the last color has a small amount of oil added to the paint. This results in a gradation of color in the spot, pale at the edges and more dense in the center. The end result gives an impression of depth that can result in some lovely patterns. These papers were very popular, in part because once the technique has been mastered, papers can be produced rapidly. There were several variations of the pattern, including a Shell on Stormont pattern and, less commonly, various combed and stylused patterns such as the fancy pattern illustrated here.