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 image, from the National Library of Ireland, shows "I" Company Auxiliaries, under Platoon Commander C.E. Vickers (beside driver), at Amiens Street station, now Connolly Station, Dublin, in 1920.

So how did Breslin choose what colours to use? "Often confused for each other, the Auxiliaries and the Black and Tans nonetheless shared similar types of uniforms, a mix of RIC dark green and British Army khaki," he says. "Given the different hues of coats in the original black and white photo, we went for a mix of green and khaki coats here too."

Accessories and background had to be right too. "Most are wearing scarves and glove it seems," says Breslin. "Hats (Balmoral caps) are dark with yellow badges. We chose an army green for the armoured cars/transporters, and added blue to the "Way Up" sign at the station, and a blue sky [with] light clouds."

Image used by kind permission of the National Library of Ireland.