High-Tech Magic


The science fiction writer Arthur C. Clarke is often quoted as saying that, “Any sufficiently advanced technology is indistinguishable from magic.” In today’s world, with miraculous technology all around us, one often takes this “magic” for granted. Once in a while, though, it’s possible to be surprised and delighted by the capabilities of our high-tech hardware and software. Here’s an example.

Recently, one of my colleagues found a set of color 35mm slides dating back to 1968. The slides were produced by the British Museum as part of an instructional packet titled “Writing in Ancient Western Asia.” The images depict examples of ancient writing, things like Cuneiform tablets and inscriptions in stone. The packet binder was shelved like a library book and sat unused in our reference stacks for decades.

We felt that the slide images could be useful for teaching, but were dismayed to see that almost all of them had undergone significant color fading to the point where they were almost completely red in tone. The images in color film are made up of transparent magenta, yellow and cyan dyes. In older types of color film, these dyes can be unstable and fade over time. For these particular slides, the cyan dye had faded, leaving the magenta and yellow image components to create a red appearance.

I have a good mid-range 35mm film scanner, a Nikon Coolscan 4000ED. The scanning software application that controls the device has a number of optional filters (software algorithms) that can be used when scanning film. One of these is a fairly popular system called Digital ICE, which removes scratches and dust from scanned film images. The other is called Digital ROC.

ROC stands for “Reconstruction of Color.” It is one of several scanning algorithms developed originally by a company calling itself, appropriately enough, Applied Science Fiction (now owned by Eastman Kodak). I figured that rather than trying to color-correct the slide scans in Photoshop, I would see if the ROC filter could correct the images automatically.

Scanned slide comparison. Top image was made without any special processing. Bottom image shows the results of the ROC filter.

The results are pretty amazing. I’m not exactly sure how ROC works, but it must analyze the image and make some (pretty good) assumptions about which dye layer has faded the most. Then it corrects the image during the scanning by restoring the lost color. This takes time—scanning with the filter enabled is pretty slow, but the results are, in a word, magical.


6 Responses to “High-Tech Magic”

  1. 1 Susan J Allen

    What about all of us who have moved on with Photoshop and are now running CS5. Kodak is in bankruptcy and I doubt they are focusing on upgrading the program as great as it appears to be

    • Hello:

      We’ll have to see if Kodak, in whatever form it takes after its reorganization, retains this software division or if they sell it off. I know that there are other scanners out there that include some form of this type of color restoration software, even if it’s from some other company.

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