I uploaded the basic image ages ago but it was brightly coloured. I wanted it to look hand-coloured, I decided, so I converted the whole image to mono and then used a large soft-edged Photoshop "brush" with low opacity, set to Linear Dodge (Add). This makes it possible to build up subtle colour to achieve the required effect. Inspired by Radim Malinic - catch him at brandnu on the internet.