Mr. Pritchard was the first customer for tar about whom the Chartered made a note. He wanted to know about using tar for 'refining oils and making japan'. A Mr. James Crease who was an established varnish maker with a business in Smithfield followed this enquiry with one of his own. He too was interested in tar for 'japan'.
In giving evidence to the 1809 Enquiry Accum had said that 'the asphaltum could be mixed with the distilled spirit' and used as 'an ingredient for making the black varnish used in japanning'.
'Japan', in this context, is the name of a technology. 'Japanning' is a method of applying a decorative coating by a heat treatment to goods using a varnish mix, which could include, for instance, coal oils. In particular this was done in the manufacture of decorated tinware in South Wales. The practice was, however, very widespread and the term appears to have been used to cover goods, like leather, which could not have been subjected to high temperatures.
In this period London directories list a wide range of manufacturers and sellers of ‘japanned’ goods. It was a popular form of decoration and no doubt manufacturers were hoping for a cheaper means of production. Gas company promoters naturally saw it as a technology that might provide an opportunity for the use of coal tar. At the 1809 Parliamentary Enquiry the Chartered Company's promoters put forward two 'japanners' to give evidence as witnesses. Neither has been traced through directories or relevant sources as active varnish makers in London at this time.
Coal tar used as paint seems to have applied to the cheaper and rougher end of the market. Japanning was a decorative, often expensive, process. There were several japanners working in London but the use of coal tar distillates for the process is not something they were likely to advertise - they were, in any case, likely to keep their mixtures secret from rivals. Because of this secrecy and despite these experiments on tar distillates it is probably impossible to know if tar was used commercially to any great extent by japanners in London, or elsewhere.