A wildlife ranger strokes a northern white rhino, only three of its kind left in the world, ahead of the Giant Club Summit of African leaders and others on tackling poaching of elephants and rhinos, Ol Pejeta conservancy near the town of Nanyuki, Laikipia County, Kenya, April 28, 2016. (Photo by Siegfried Modola/Reuters)

Paul Poirier of Canada and Marjorie Lajoie of Canada after training before the Figure Skating Ice Dance – Rhythm Dance at Capital Indoor Stadium in Beijing, China on February 12, 2022. (Photo by Aleksandra Szmigiel/Reuters)

Peter Carberry riding Gabbys Cross falls off during the Randox Grand National Chase during day three of the Randox Grand National Festival at Aintree Racecourse on April 15, 2023 in Liverpool, England. (Photo by Michael Steele/Getty Images)

(L-R) Ryan Regez of Switzerland, Tyler Wallasch of USA, Sandro Siebenhofer of Austria and Ferdinand Dorsch of Germany during the men's quarterfinal heat 4 during the men's Ski Cross final at the FIS Freestyle Ski World Cup event in Idre, Sweden 23 January 2021. (Photo by Pontus Lundahl/EPA/EFE)

A man carries his wife on his back as they make their way with their luggage along a flooded tunnel to catch their train, after heavy rainfall hit Jinhua, Zhejiang province, China, July 21, 2015. (Photo by Reuters/China Daily)

Performer from the Mangueira samba school parades during carnival celebrations at the Sambadrome in Rio de Janeiro, Brazil, Tuesday, February 9, 2016. (Photo by Silvia Izquierdo/AP Photo)

Women from a local cocoa farmers association called BLAYEYA work in a cocoa farm in Djangobo, Niable in eastern Ivory Coast, November 17, 2014. BLAYEYA is a women's only association with each member owning a field and planting cocoa. (Photo by Thierry Gouegnon/Reuters)

Photochromes are vibrant and nuanced prints hand-coloured from black-and-white negatives. Created using a process pioneered in the 1880s, these images offer a fascinating insight into the world when colour photography was still in its infancy. A Tour of the World in Photochromes is at the Swiss Camera Museum, Vevey, until 21 August. Here: Street food in the Strada del Porto in Naples, Italy, 1899. (Photo by Swiss Camera Museum/The Guardian)