inscribed (vertically) in blue pencil on reverse c.r.: Otira Gorge / Used for process / 1-1-91 inscribed (vertically) in pencil on reverse u.c.: Otira Gorge (underlined) / 30/1/90 same size (all underlined) stamped (vertically) in purple ink on reverse u.r.: C. WELLS / 24, BOUVERIE ST / LONDON E.C. / INVENTOR & MAKER
