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WEB PRINTING SPECS -- SWOP for the New Millennium

September 2001

The specifications, first designated SWOP in 1976, addressed fundamental color reproduction principles that had been discovered in previous decades of printing technology development. This included substrate, inks (hue and density), tone reproduction (or dot gain, as it came to be characterized in halftone printing), gray balance, screening, trapping and many other parameters that need definition and control for consistent color reproduction.

The founders of SWOP wisely recognized that the specifications needed to be clear, reasonable targets achievable by a broad and developing industry, rather than a narrow window limited to an elite market. They also realized the importance of having each segment in the production chain take responsibility for supporting and adhering to the specifications.

Matching Color On-press
The result was a uniquely cooperative effort that benefited everyone in the publication industry. The problems of color matching on-press, once chaotic, continually improved and eventually the creative segment of the industry could count on their work being reproduced faithfully.

It is important to note that SWOP does not profess to be a standard in the formal sense of the word. It is a specification that, in describing procedures and parameters, refers to accredited standards that formally document the accepted way to accomplish reliable communication in open environments.

SWOP is careful to avoid policies that hinder internal operations of, or cooperative participation by, any of the enterprises in the graphic arts chain. While SWOP's mission has been targeted at the magazine industry, its principles have benefited a much broader printing industry. Surveys have shown that it has become a recognized guide synonymous with basic color reproduction to some, but to others it is quite misunderstood, though often quoted.

Indeed, with problems of color quality in great retreat by the early 1990s, the original SWOP mission had been forgotten by many and the name became associated more with print commoditization than the improvements for which it had been so instrumental.

Enter the digital era. Throughout the '80s and '90s the digitization of the graphic arts process—from creation to production—provided a new basis for economy and efficiency in the printing industry. It also provided new challenges for maintaining the quality and reliability required in the high-stakes business of long-run publishing and advertising.

Communication between agency, prepress, publisher and printer, which had been normalized over the years under the influences of SWOP, had taken a turn. Digital data hidden in a myriad of file formats and color proofs with diverse reproduction characteristics were recreating a dilemma reminiscent of that experienced 25 years earlier.

To address these challenges, SWOP has reaffirmed its mission and responded with initiatives intended to facilitate reliable communication of color information in the digital domain. These initiatives form much of the important new material in the 2001 SWOP specifications.

Anticipating future need for communicating color in an objective and numerical fashion in the digital age, SWOP partnered with CGATS (the ANSI Committee for Graphic Arts Technical Standards) in the mid-'90s to define and characterize publication printing.

Careful press tests with the standard IT8/7.3 data targets were conducted and extensive measurements were performed. The resulting ANSI CGATS.6 standard and accompanying TR001 technical report document the reference printing conditions for SWOP printing and the complete colorimetric characterization for those conditions.

This data can be used to make color management profiles and as an objective target for SWOP digital proofing. In the new specification, SWOP asserts that ANSI/CGATS TR001 defines the color characteristics of SWOP-certified press proofs and specifies that it be used for color-managed applications such as remote proofing. (TR001 documentation and data is available from

Next, to assist in the successful implementation of digital proofing technologies, SWOP has developed a certification program for the first time. The challenges brought about by the diversity in digital proofing systems and the potential for non-controlled color characteristics have prompted the need for this program.

To apply for certification, vendors must submit proofs of a standard test form along with an Application Data Sheet (ADS) that details precise procedures and parameters needed to make the proofs.

To achieve certification, the submitted proof must be consistent with the ADS and must be deemed acceptably close to SWOP-certified press proofs in blind evaluations by experienced color analysts.

SWOP-certified Proofs
This program is aimed at promoting proofing systems that are reliable and user-friendly, without requiring a color expert. SWOP specifies that only SWOP-certified proofing systems be used in supplying color proofs. It is also important to note that the certification implies only that a system is capable of producing a SWOP-compliant proof. The proper creation of a proof per the ADS, along with a color control bar, is the only way to ensure that an individual proof is truly acceptable.

Readers of the new specifications will notice that, while reiterating all the details that have become part of SWOP over the years, there is an additional emphasis on the burgeoning importance of digital workflows that culminate in CTP production.

Special aspects of tone reproduction, screen angles, minimum dot, color control bars and formats as they pertain to digital production are identified, highlighted and discussed.

Perhaps most significantly, SWOP has specified that the exchange of print-ready digital information should occur using the standard formats TIFF-IT (ISO12639), PDF/X (in development as ISO15930) and their future derivatives. This is a natural extension of the notion that digital delivery must become as reliable as supplied film became in previous decades.

Finally, SWOP has recognized the need to educate a new generation of professionals who are merging graphic arts with graphic technologies. It has sought close ties with other organizations involved in the evolution of digital production in the graphic arts. It has recently established a close alliance with DDAP (Digital Distribution of Advertising for Publications Association, and the Digital Ad Lab (

SWOP has continued its participation with CGATS, and has continued to enlarge the scope of organizations represented on its board and review committee. It has realized it must reestablish a clear understanding of what SWOP has been and will become in the future. To this end, SWOP has taken steps to reaffirm its trademark and ensure that vendors—who have so liberally used the SWOP name in the past—give proper attribution and, most important, correct citation.

Though the digital revolution has been maturing for some time, there is still a long way to go. The printing industry in the U.S. has probably not yet passed the half-way mark for CTP adoption and it is probably less accepted worldwide.

While much of the delay is simply the massive inertia of a large industry, there are still perceived obstacles in transitioning from a modality that served so well for so long. Two of the most quoted concerns are the reliability of file formats and the integrity of digital color proofing.

Yet almost everyone acknowledges digital is the goal and it is clear that the appropriate technologies are available. But it is the refinement of implementation and practice that is needed to give decision-makers the confidence that their investments will reap the promised benefits. This is exactly what SWOP accomplished in another era of technological transition and is exactly what it aspires to do again.

The fact this is being realized by wider segments of the graphic arts industry is shown by the initiatives such as GRACoL (General Requirements for Applications in Commercial Offset Lithography,, which is setting the groundwork for similar specifications across many other segments of the printing industry.

Newspapers Follow Suit
Other trade organizations such as the NAA (Newspaper Association of America, have emulated the SWOP specifications with SNAP (Specifications for Non-Heatset Advertising Printing) and are seeking to further characterize newspaper color as SWOP and CGATS did with TR001.

ANSI/CGATS and ISO TC130 committees continue to develop standards that will facilitate reliable implementations of digital production across all industry segments.

Ultimately, standards will be built into the operating infrastructure of the industry by vendors who can trust they won't have to continue to develop for moving targets.

Eventually, this overall scenario will reiterate when the next wave of new technology is born. However, by then the methodology will have become more familiar because we will have learned how to optimize technical communication in our commercial environments.

The 2001 edition of the SWOP specifications was prepped according to the practices outlined in the manual at Phototype Color Graphics in Pennsauken, NJ, and printed at R.R. Donnelley's Mendota, IL, facility. Copies are $12 (less for quantity orders) and can be ordered from the SWOP Website at under "products."

Visit for information on applying for certification.

About the Author
MICHAEL RODRIGUEZ has been involved with various aspects of digital imaging and color reproduction at R.R. Donnelley & Sons for the past 15 years. He has also been actively involved in promoting industry cooperation and education concerning color and file standards for the graphic arts. He is a board member of SWOP, an executive committee member of DDAP and CGATS, and a steering committee member of the ICC (International Color Consortium).

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