Ralph Hope-Johnstone was a hydro-electric engineer and photographer who worked with Olegas Truchanas on the campaign to save Lake Pedder in the late 1960s. Together, the two men assembled and organised widely-attended screenings of an audio-visual presentation on Lake Pedder, aiming to show Tasmanians and the wider world what they stood to lose. Peter Dombrovskis's photographs were often shown on these 'slide nights' as well.