Original Johnsons of Hendon Unitol concentrated fine grain developer calculator and instruction card, issued June 1961. Features the circular developing-time calculator with dilution, temperature and developing group scales, plus detailed instructions for film, plate and tank development. A great piece of vintage British photographic darkroom ephemera for collectors of analogue photography, film processing equipment and Johnsons of Hendon memorabilia.

Vintage used condition with visible age-related discolouration, surface marks, creasing and wear around the edges and corners. There is also handwritten pricing/notation to the front. Central calculator assembly is present; no claims are made regarding accuracy or practical modern use. Please see photos for exact condition.