Keith Haring

Haring drew in a line he never varied — the radiant baby, the barking dog, the crawling infant, the dancing figures — first in white chalk on the black paper covering unsold advertising panels in the New York subway, thousands of times between 1980 and 1985. He was in the Whitney by 1982, opened the Pop Shop in 1986 specifically so the work would stay affordable, painted murals worldwide, was open about his AIDS diagnosis, and established a foundation before his death in 1990 at thirty-one. The career is ten years long, and the market has to work with what that produced.

Authentication is the dominant fact. The Keith Haring Foundation dissolved its authentication committee in 2012, so no body now issues opinions on attribution, and that has thrown everything onto provenance. Where has the work been, which gallery handled it, is there documentation from the period. The subway drawings on paper are the single most faked category in the market — they were made in enormous numbers, in cheap chalk on cheap paper, frequently removed by passers-by, and the resulting supply of undocumented sheets is exactly the environment forgery thrives in.

The prints are the most tradeable part of the output and the most straightforward to identify: documented editions, published dates, recorded sheet sizes, pencil signature and numbering. Those are the works most owners hold and the ones where a valuation can be arrived at with confidence. Against them sit Pop Shop merchandise, posters and licensed product in vast quantity, all of it legitimate and almost none of it a limited edition, whatever the listing says.

Condition is the last variable and a real one. Chalk on newsprint-grade paper is about as fragile as works on paper get. The Pop Shop and subway material was never made to last, the papers acidify and the media abrade, and a sheet that has hung on a wall since the eighties has usually paid for it.