I was quite pleased to stumble upon a series of photographs taken in the Himalayas by David Breashears and his GlacierWorks team in late 20007-8 from the same vantage points as black and white photos from as far back as 1899. I realized that I could borrow the colors from the new photographs and apply them to the old photographs. The thought of placing a color camera in the hands of George Mallory (of “Because it’s there” fame) as he faced the Rongbuk Glacier in 1921 was thrilling. I did not want to do any airbrushing – the color added to the old photo should be as true as possible to the new photo. I split the colored version into color, hue, and lightness channels, I then combined them back together using the old 1921 photo in place of the lightness. The result was close to what it must have looked like in 1921, with odd exceptions. A small purple anti-cloud hangs over Mt. Everest. A few minor snow fields that existed in 2007 but not 1921 show as bizarrely colored stripes or dots – the algorithm used to extract hue and saturation values has the same problem a human does when pondering what the color of white is.
But of far greater concern was the differences in the glaciers. In 1921 the left side of the valley bottom is filled with clean ice coming from the main branch of the glacier. The right side is dominated by a dark tongue of dirty ice coming in from a side-glacier. By 2007the glaciers have been decimated. The dirty ice from the glacier on the right has dwindled, allowing the ice from the main glacier to flow closer to the valley center, but it too has decreased substantially, now a thin strip of blue ice flowing down a small dirty river that is more rock and dust than ice. The result in my colorized photo is a large stripe of blue in what should be gray ice. The clean ice to the left should have a slight blue cast to it but is instead slightly tan. Climate Change is messing up my time machine.