Here is a description of techniques of image making in the eighteenth century, which seems to contain a description of someone working very like Jackson Pollock, as well as some early graffiti-artists:

I cannot help thinking, that the admirers of strong rough pictures are, in general, men of enlarged ideas, and frequently possessed of the wonderful talent of making portraits in the fire, or forming fanciful landscapes upon old broken walls, or any other place where there happens to be an assemblage of spots and blotches. – I am informed that a person of Birmingham acquired a considerable fortune by indulging a similar turn of mind. – He was so well convinced of the prevalence of this taste, that he established an academy for the purpose of promoting this style of colouring, and of producing pictures for the exercise of Fancy. These pictures were dispatched by placing five different colours at hand, dipping the ends of the fingers and thumb in these colours, transmitting them to the lid of a snuff-box, and then splashing the colours into confusion by striking them with the palm of his hand.”

Joseph Booth, A Treatise Explanatory of the Nature and Properties of Pollaplasiasmos, London:1784.