Rare 1972 silk screened version. There is a more common litho version from 1970 that is very pale and dull.
It was the only litho the company did and they had a ton of those printed. There is no substitute for the bright chalky solvent based inks they used and screened by hand. This poster is from the last days of the company, when production had pulled way back.
It all makes this a pretty rare version of the most prolific poster they did. Full sized vintage original poster.
Hand screen printed by Houston Blacklight Poster Company in 1972. Size is 23 x 35. Poster is new old stock, in near mint condition.