Host's latest show spans the spectrum of monochrome from 1859 to 2007, offering a reminder that while black-and-white photography was once a restriction, it's now a choice.

Taking in ten pioneers of the medium, the exhibition places all pieces on an even footing by using a new kind of photographic paper that can create silver gelatine prints from digital images.

Some works look startlingly modern. Eadweard Muybridge shot a 360-degree panorama of San Francisco in 1877 which took five hours to complete, each shot lasting around 20 minutes. Yet it wouldn't look out of place on a postcard today, crisp despite the long exposures.

Gary Knight's images of Darfur, meanwhile, show how the format is able to relay issues in shades of grey. The edge of a hijab or the white of an eye gleam out at his lens, creating a striking contrast in his works.

Maurice Broomfield's collection records a Hollywood glamour on the factory floor, framing one worker inside a giant cog and another between the huge metallic dorsal fins of a propeller.

Next to them, Cornel Lucas's portraits of film stars capture the mundane as well as the iconic, with a grid of facial expressions pulled by Bob Hope resembling a sheet of photos from a passport booth.

Until May 4, Mon to Fri 10am to 6pm, Sat 11am to 4pm, free. Tel: 020 7253 2770. www.hostgallery.co.uk Tube: Barbican/Old Street