Judith Black's best photograph: my family on Father's Day

‘I took group shots of my children whenever they were about to go away on holiday. I’d use them as bookmarks. It meant I still had them with me’I took this portrait of my family on Father’s Day in 1983. At the back there’s Rob, my partner and the children’s stepfather; then my eldest, Laura, with the curly hair; and Dylan, my youngest, with the homemade bowl cut. And in front, there’s Erik and Johanna. The dog was not ours; we were looking after him. Rig