500 Rials - Mohammad Rezā Pahlavī 7th. portrait, 'Dark Panel'

By the late 1960s, Harrison & Sons had become the dominant printer for Iranian paper currency, a relationship that would persist until the Revolution made British involvement politically untenable. The "Dark Panel" designation distinguishes this issue from earlier 500 Rial notes in the same Pahlavī series — the tonal shift in the underprint was a deliberate security modification, not a design refresh, intended to complicate photographic counterfeiting at a time when that method was the primary threat.

Pick 88 sits at the upper end of the denominations in everyday circulation during Iran's oil-boom expansion. High-value notes from this period often show heavy fold wear; the 160mm width made wallet storage awkward.