New photo-colorizing process factors in the reactions of the skin to the light

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Image: Time-Travel Rephotography

A century ago, film stocks were not limited to capturing only black and white details, but they could only pick up a limited band of colors and images of well-known individuals who didn’t exactly portray how they were looking. Thus a new colorization approach with AI finally takes this into account, which produces eerily lifelike photos which appear to be grabbed by a modern camera.

All of us saw old black and white pictures of the dirty, bruised and shallow photo of Abraham Lincoln, which focus only on a part of his portrait. The low-quality images are the result of the limited capacities of the cameras and the lens at the time, but Lincoln looked more skin-ridden and appeared to desperately need a moisturizer.

Before 1907, most stocks of black and white films were orthochromatic and were sensitive to visible light except the colour-spectrum portion, in which warm colors such as red exist. Some of it bounces down when light touches human skin, but some also penetrates the surface and lights the skin from the inside, which makes natural traits such as wrinkles less apparent. It is a sub-surface effect, a disbanding effect which years ago finally brought about a real revolutionization in computer graphics and a much greater life-like appearance of virtual objects, but the effects of sub-surface scattering, while visible to the human eye, are not recorded in orthochromatic film stocks.

As a result, in black and white photographs Lincoln always looked especially old. Traditional colorisation techniques fail to take account of what really happened to old film inventories. The images are rusty, enhanced, sharpened and naturally colored, but colored photos are no longer capable of captured by old black and white cameras that reintroduce natural light softening effects on the hair.

AI-powered image processing has been going on in a couple of years and a new coloring technique called time-travel photography delivers impressive results not only by adding color, but also by referring to the photos taken with modern digital cameras to make adjustments to human skin. A research team at the University of Washington, UC Berkeley and Google Research developped the new technique (detailed in a recent paper) and it starts by an AI trained in modern digital portraits to create a sibling photograph, which shares many feasible colors of the original black and white subject, but with different identities.

The photographing process for timescales can also determine how the limitations of an antique camera degrade the resulting black and white image and correct the problems when the colorized styling of the modern sibling photo is applied to the originary B&W photograph. This includes the lack of sharpness, contrast and exposure. This results in a new photo that looks like a modern DSLR and a high-quality portrait lens, despite the death of the subject a century ago. The picture is fault-free.

A classic portrait of Nikola Tesla colorized and enhanced using the new Time-Travel Rephotography technique.
Image: Time-Travel Rephotography

The results of the new technique of colorization often seem incredibly vital, and it helps to humanize people who grew over decades into mythical figures.

But it is also important to bear in mind that colorizing and modernizing images are a process that introduced subtle changes and changes to the original – such as the imperfections when copying a document – and, over time, since these modified images have been released into the wild of the internet and processed in addition (even image compression often affects an image negatively).

As AI image processing progresses year after year, it becomes desperately necessary for images to be authenticated or for images to be properly marked that have been edited or enhanced. This is why Adobe and other companies have developed the Content Authenticity Initiative as a way to capture photos with a record of who manipulated them over time, while others have pointed to the Blockchain as another way to track the authenticity of an image.

The journey of time Photography does not always have a bad effect: the technology makes a lot of use of historic figures who lived before film pictures, TV and sound recordings, and tools like MyHeritage’s DeepNostalgia can help people overcome grief or other unprocessed emotions associated with a loved one’s loss. But instruments such like this become a problem when artists are accused of adding sourires while colour, for future generations of people, of the victimizations of the Khmer Rouge regime’s torture prisons in Cambodia, potentially minimizing these events.