Many years ago I was in Cuba. I ate some bad chicken. After a strong course of antibiotics I got over it. But ever since - can it be coincidence? - I have had a ghostly apparition in my right eye. Only visible in full sunshine (and so rarely seen in Manchester) it hovers just on the fringe of my vision and consciousness. It is probably some dead amoeba or something. The optician told me to forget about it. But, as a photographer who lives through noticing the imperceptible, I decided to dedicate an exhibition to my univited companion.