Another choice for 4K scans is the Northlight from FilmLight Limited, an independent U.K. venture founded by the technology team at Computer Film Company (CFC), a pioneer in the DI process. The fourth-generation Northlight offers high resolution and also provides image stability with a pin-registered gate design. A single machine can scan images at 2K resolution continuously at 24 frames per minute. Originally marketed by the now-defunct ITK, Northlight can be found at Framestore CFC in the U.K. and at Technique, Pacific Title and Imax in the United States. FilmLight just announced Truelight, due to ship in 2003, a "no-compromise" color management system to enable accurate previsualization of final projected film images on electronic displays.  FilmLight will also soon preview new (but undescribed as of yet) grading and film finishing tools, making it an all-in-one solution for digital mastering.

Not to be outdone, Cintel also offers a 4K-resolution machine, the DSX. Soon to follow is the Thomson/ Grass Valley Spirit DataCine 4K, which is scheduled to launch at NAB this month. The Spirit 4K is designed to scan 2K images in real time and 4K images at anywhere from 6 to 8 fps. It offers built-in 4K primary color correction and negative matching, and a real-time scaling engine that can convert 4K scans to 2K. The Spirit 4K uses a Kodak-designed high-resolution advanced imaging subsystem, which features diffuse light, custom optics, optical film matching and optical gain control, as well as the new Gigabyte System Network (GSN) interface, a high-speed data pipe that enables the transfer of transparent 2K data in real time and 4K data at 6-8 fps by using less than the available GSN bandwidth, leaving room for other applications.

The enhanced picture resolution of the 4K scanners is important, but of equal if not greater importance is improved color resolution. Whereas early systems were saddled with a sub-sampled chroma of 4:2:2, most now offer full bandwidth 4:4:4 color. 4:2:2 describes the ratio of sampling frequencies used to digitize the luminance and color difference components of component video, meaning that for every four samples of Y there are two samples each of Cb and Cr. CCIR 601 component video uses 4:2:2 for the standard digital interface between main digital studio equipment. In the 4:4:4 ratio, there are always an equal number of samples of all components. "A significant increase in color resolution far outweighs the additional increase in pixel resolution," says Sunset Digital CEO/founder Ron Burdett. "Now you're dealing with full bandwidth color, which gives better fidelity and resolution." Adds iO Film's Bruce Johnson, "It all comes down to what colorspace you're comfortable working in. The EFilm method retains the maximum amount of colorspace, with a 10-bit log in a Cineon file format, whereas when you do the HD-to-film route you're down to 8-bit YUV color."

One of the systems that has attracted the most attention is Colossus, formerly marketed by 5D and now part of Discreet's stable of products. Used for the Lord of the Rings trilogy and Stuart Little 2, among other films, Colossus features technology developed by Colorfront, a Hungary-based company founded by Mark Jaszberenyi. As founder of a film postproduction company, Jaszberenyi realized that there was no good tool for enabling a cinematographer to manipulate film footage in the computer. "We were using the tools available, but they weren't

really designed to manipulate the whole feature film - they were visual-effects tools designed to work on one shot at a time," he says. "Cinematographers were asking me for tools that would be similar to what they had for working on commercials."

In 1999, Jaszberenyi started Colorfront and developed Colossus, a software-based, digital grading and finishing solution. The scene-based color-correction tool is designed to make the grading of multiple scenes as fast and as efficient as possible. Running on commodity workstations, its internal architecture is 16-bit/channel linear or log processing, depending on the user's preferred method. "Colossus is a film tool," stresses Jaszberenyi. "It's designed for the film environment and work in the lab. We have a film-lab background, so we know the technology and the terminology. And Colossus fits into the workflow - you can custom-calibrate the system like you can in a specific lab."

"In my opinion, Colorfront is the best color grader for motion pictures available at this time," says Stuart Little 2 cinematographer Steven Poster, ASC. "Software that's friendly to cinematographers is what's important to facilitating a smooth transition to [using a DI]. It has to allow us to do the kind of things that are necessary in motion pictures, as opposed to working on the telecine for television."

Many facilities do rely on traditional telecine tools, such as the Pandora Pogle/MegaDef or da Vinci 2K, and they have their defenders as well. "With the Pandora MegaDef and da Vinci 2K, you can simultaneously move the knobs to change black level and gamma," explains John Dowdell, chief imaging officer of Technicolor Creative Services-New York. "They're designed for multi-tasking. You can separate and color-correct the layers with the Colossus, but with the da Vinci or Pogle we're generally working with a composited image. It's a different way of color-correcting."

Notes Post Logic's Birstock, "We're making sure that the transition into the DI world from the telecine environment that so many filmmakers are used to is a comfortable one." Post Logic offers two C-Realities with the Pandora Pogle and da Vinci 2K.

The Quantel iQ is another tool adopted by some for its ability to work with multiple-resolution sources in a resolution-independent environment, with approximately 9 terabytes (TB) of storage. Post Logic has the iQ, and Sunset Digital is considering it. One way Modern Video Film uses its iQ systems is as a server for the da Vinci 2K Plus. "The Quantel iQ is a creative tool set that in some cases overlaps with that of the da Vinci and, in many cases, augments it," says Moshe Barkat, Modern Video Film president. "We have several iQ systems, and the one we use in the theater has the abilities to edit, conform, rearrange sequences and drop in shots when they come in late during the color-correction process."