Contact Sheets: Pollution (Schools) and Alchemy Three sets of contact sheets for the Northcott Young People's Department schools production Pollution, showing negatives numbered 172/9/1-12, 172/10/1-12, 272/10/1-36, 272/11/1-36 & 972/21/1-36 taken by David Gorring. Also includes a set of contact sheets for Alchemy (no reference numbers) taken by David Gorring and prints from both productions 17 & 22 May 1972