In his Old Ireland in Colour project at the Insight SFI Research Centre at NUI Galway, Professor John Breslin uses DeOldify, an open source tool, to bring colour to archive images. This photo from the National Library of Ireland's collection shows British soldiers of the Loyal North Lancashire Regiment searching a train in Co. Kerry. 

So how did Breslin choose what colours to use? "We chose khaki as per British uniforms worn around this time and in World War I," he says. "The helmets are often a greenish colour as per pictures and photos of period army gear. Regiment shoulder titles and buttons are gold, again as per photos of period items. We enhanced the sky to be more blue and fixed various blemishes on the photo in Photoshop."

Original image used by kind permission of the National Library of Ireland