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Color Scanners--The Color of Digital Originals

June 1998
BY MARIE RANOIA ALONSO


Handling the sheer volume of scans seems to be a more daunting, more demanding task. It isn't solely the imagination of your prepress manager.

Lucky for the prepress manager, scanning has been brought to an all-time level of ease, thanks to a robust product market laden with devices that boast built-in gradation curves, preset color look-up tables and expanded capabilities to digitize reflective and transmissive art at an impressive array of scanning depths and optical densities.

From the AgfaScan T-5000 from Agfa Div., Bayer Corp., to the vertical-drum Tango from Heidelberg Prepress to the Fuji C-550 or the EverSmart family from Scitex, the field of devices from top vendors the likes of Anitec, Epson, Howtek, ICG North America, Kodak Professional, Optronics, Purup-Eskofot, ScanView, Screen, UMAX and others is impressive.

Color is the shared focus.

While color issues on the input side are clearly not as provocative or controversial as are color concerns on the output side, there is still much room for deliberation.

What are scanning trends today?

  • The migration from scanning in CMYK formats to the CIELAB format, which offers flexible re-purposing using ICC-standard profiling, is promoting faster adoption of device-independent, multimedia publishing workflows.

  • The move away from CMYK-specific scans to RGB-specific scans to, again, adopt true device-independent scanning.

  • The expectation for Pantone's Hexachrome to carry new levels of color to the scanning environment.

  • The emergence of the need for multitasking workstations, all feeding into one server, all linked to the same color management tool, empowering a series of scanners.


Don Rogers, product manager for scanning systems at Heidelberg Prepress, offers a CIELAB perspective on CIELAB significance.

"An important factor in the scanning process today is the clear benefit of scanning directly into CIELAB. CIELAB scan data can be used again for different CMYK requirements, or even different RGB requirements, just by attaching the correct output profile," Rogers explains.

The migration from scanning in CMYK formats to the CIELAB format, which offers flexible re-purposing using ICC-standard profiling, is promoting faster adoption of device-independent, multimedia publishing workflows, asserts Rogers.

"Apple and Microsoft have become serious in their involvement by utilizing Heidelberg's LinoColor CIELAB-based color management engine in their operating systems," Rogers reports. "The move to CIELAB scanning is further fueled by moves to make CTP devices, as well as RIPs, part of the ICC workflow."

Scitex implemented the ICC concept into its scanner activities years ago, with tools that are continuously being updated as technologies become available, reports Ziv Argov, product marketing manager for input systems at Scitex America.

"The EverSmart application is a complete ICC solution. The scanner is able to capture the maximum density with the accurate color and details using its XY scanning technology," Argov states. Looking at the EverSmart, information is stored as the scanner originally sees it—an RGB file.

An input ICC profile can be embedded to each scan. The preview picture is displayed automatically using the default system ICC display profile.

"The ICC concept has given the industry a standard way of transforming colors, but the transformation is still dependent on the original data quality," Argov explains.

Still, there is a great deal of opinion regarding the complexity involved within ICC profiles.

Why? Well, from an input device standpoint, creating an ICC profile today does not necessarily mean color will be matched properly on the output side—where the rubber meets the road, as Allen J. Dunn, senior product development manager, Electronic Imaging, Fujifilm, explains.

"While the concept of profiling and using ICC profiles is somewhat common for input devices, it's using these profiles and actually having an impact on output devices, such as color proofers, where the real challenge begins," Dunn contends.

At Fuji, which recently launched the C-550 flatbed scanner featuring optical resolutions of up to 5,000 dpi, in addition to work with ICC profiles, research is being done to close the color loop with the help of Pantone's Hexachrome technology.

"We find Hexachrome solves a lot of color issues, as they relate to spot colors," Dunn reports. "We can actually scan Hexachrome, with our scanners working interactively with Hexachrome—because of this, we've obviously stepped up our relationship with Pantone."

Hexachrome is a standardized, ultra high-fidelity process printing system developed by Pantone that incorporates six ink colors as opposed to four. The six inks are modified, more vibrant versions of cyan, magenta and yellow with the addition of green and orange. Black is the sixth color.

At Kodak Professional, Hexachrome sets the expectations of the scanner. Kodak is also committed to the scanning movement away from CMYK-specific output to RGB-specific output, as Chris Heintz, program manager for Color-Flow, reports. "People want to scan an image once and use that scan as many ways possible, across as many varying media as possible, including output on the Internet," Heintz states, noting the move away from CMYK scan is the concept the future will necessitate.

At Optronics, the ColorGetter team has released the new ColorRightPro 1.0 for Macintosh, Windows 95, and Windows NT, and is also issuing updates to the popular ColorRight 5.2 for the Macintosh, and ColorRight PC 3.5.2 for Windows 95 applications early this summer.

"We are now focusing on new challenging scanner issues—these are both hardware and software based, and look to automate the high-end scanning process," reports Mike Mello, product manager for scanning systems at Optronics.

The future of scanning is calling for different workstations, feeding into a server, running multiple scanners, each of which is digitally armed with a color management tool. A prepress department can then manage all aspects of the scanning workflow, reports John Lang, product manager for color systems at Agfa Div., Bayer Corp., which promotes ColorTune color management software.

Is there room for improvement?

Agfa's Chris Parent, product marketing manager, fields this question.

"Truth? It's going to be awfully hard to get any better, more economical and technological scanners, but we could, as an industry, offer improved color fidelity and a greater bit depth."

For a list of scanners, consult Printing Impressions' annual Master Specifier next month.


Ask an Expert
Will We Need to Change the Way We Scan Color?


Don Rogers, product manager for scanning systems, Heidelberg Prepress

Yes. In fact we are already seeing a move away from traditional CMYK scanning techniques. This is primarily due to both the need for re-purposing of scan data, as well as color management tool improvements.

Although high-end scanning methodologies have been used in CMYK formats to ensure high quality for commercial printing results, there are many factors that, in sum, make these techniques less efficient for today and the future.

When the final goal was to produce film and an analog color proof that represented final press conditions, scanning internally with the "known" conditions that covered paper, ink, dot gain, screen ruling, UCR, GCR, etc. was best accomplished by scanning directly to the CMYK output format.

Today's multimedia output destinations (print, CD, Internet, etc.) require that scan data be processed in a way that will deliver the best results no matter what the final output path or paths may be.

Even when commercial print is the only goal, the number of companies that have multiple presses and even multiple plants make this flexibility necessary because the final location at which the job will print is not always known.

With ever shorter production schedules, the ability to process scans without knowledge of their destination is quickly becoming a requirement.


Establishing
A Color Benchmark


A talk with Christabel Chen, product line manager for scanning systems at UMAX

In order to establish a benchmark for great color in the scanning environment, it is important to understand the common problems, and causes, associated with poor scanning applications.

Three paramount challenges come to mind: poor tonal range in originals, poor RGB to CMYK color conversion and inadequate sharpening.

While poor tonal range in originals (most likely caused by underexposure, overexposure or even color casts resulting from poor film development) and inadequate sharpening (a negative side effect of halftone printing) are critical, for purposes of this article, let's concentrate on the RGB to CMYK challenge.

Assuming that the user has a good RGB file, the next issue is the conversion of RGB to CMYK. There are many options for RGB to CMYK conversions, but the issue is quality. The RGB color gamut is much broader than the CMYK color space, so the challenge is to create a CMYK combination that can closely reproduce a printed image that looks natural to the human eye.

At UMAX, PhotoPerfect uses binu-scan's Exact Color technology, which produces a digital separation that matches the quality of traditional printing separations. Exact Color allows consistent color separations to be generated, regardless of the table used or total ink coverage required.
 

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