The American Society of Cinematographers

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Return to Table of Contents August 2006 Return to Table of Contents
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Snakes on a Plane
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Imagica
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Wetgate Scanning by Imagica


Imagica, one of Japan’s leading postproduction and imaging facilities since 1935, recently introduced a 35mm 4-perf wetgate option for its Imager XE Advanced Plus 4K film scanner. The wetgate process can reduce and even eliminate dirt and scratches from scans, thus decreasing the amount of time spent on digital dust-busting and frame repair.

Time, naturally, is money, and the wetgate, coupled with the pin-registered Imager XE Advanced Plus’ fast scanning speeds — 1.3 seconds per 35mm 4-perf frame at 2K in the Cineon 10-bit format and 1.9 seconds per frame at 4K — can yield noticeable savings. (The Advanced Plus also outputs to 8-/16-bit Tiff and SGI, as well as 8-/10-/16-bit DPX formats.)

The wetgate concept, commonly found on the printing side of the post world, seems like a logical fit for scanners; the Oxberry Cinescan 6400 with a wetgate option is still used, particularly in Europe, as is the Marconi Telecine with wetgate. However, leakage and especially bubbles can plague a system.

Imagica spent about a year developing its wetgate to prevent those issues. “Bubbles have been one of the issues with any wetgate system,” notes Imagica Vice President Richard Antley. “Imagica has laid out the little ports — the holes on the gate where the liquid comes out and the vacuum sucks it up — all the way around the gate,” meaning that though the gate is vertical, the liquid remains suspended in the gate without leakage.

However, a few drips here and there are unavoidable. “The film that comes out of the gate is still wet, but it evaporates very quickly,” says Antley. “That’s what the ventilation is for.”

For $40,000, one gets the installation of the wetgate itself, stainless-steel drip pans, ventilation, and the liquid and vacuum lines. The user must supply the pump and vacuum, the filter, and the chemical solvent Tetrachloroethylene, or Perc. (Before the 1996 Montreal Protocol legislation on substances that deplete the ozone layer, Trichloroethane was the liquid of choice.)

Scratches are visible on film scans (and prints, of course) because light refracts where the missing material should be. Perc fills in the scratches and corrects the light rays. Not just any liquid will work in this manner. “What’s key about that particular liquid is a characteristic called refraction index, which describes for different materials how much they bend the light,” explains Antley. “The refraction index for Perc is very similar to the refraction index of the base of film.”

International Video Conversions, Inc. (IVC) in Burbank, California, which provides digital intermediate, digital cinema mastering, high definition and restoration services, was the first facility outside of Japan to install the wetgate on its Imager XE Advanced Plus scanner. “We found out Imagica was developing a wetgate, and I expressed interest in helping them beta-test it,” says Jim James, chief engineer at IVC. “That’s been going on for awhile; we had it installed prior to NAB. One of the first things we worked on with them was making sure there were no bubbles. In absolutely none of the scans that we have done have we seen any bubbles.”

For a scratch to be repaired digitally, algorithms must rely on the pixels adjacent to the scratch to re-create the missing information. Depending on the image background, the result sometimes can be substandard. “Scratches are probably the hardest thing to fix digitally,” notes James. “You could spend a fairly large number of hours and still not get a perfect result. [The wetgate] can completely eliminate scratches. It doesn’t just save a lot of time, it also gives you a much better final product.

“The main focus for the wetgate is older film,” he continues. “That’s where you find most of the damage. But if somebody has some film that had an unfortunate experience at a lab and is scratched, we’d love to have him come to us. They’ll get the film back as though it had never been scratched rather than have to pay several hundred hours of cleanup work.”

For more information, contact Imagica Corp. of America at (310) 277-1790, www.imagica-la.com, or IVC at (818) 569-4949, www.ivchd.com.

 

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