First Thermal Plate Tests at Tech Alert ’98

PITTSBURGH—Attendees here at the recent fifth annual Tech Alert conference, sponsored by the Graphic Arts Technical Foundation (GATF), witnessed the first detailed study comparing CTP-exposed thermal plates.

GATF designed a special digital test image for this test. The image contained vignettes and gray backgrounds to show anomalies such as banding, streaks and inconsistent imaging.

There was no real difference among any plates in dot imaging consistency. The Kodak DITP, Fuji LH-P and Fuji LH-N plates had the broadest highlight to shadow dot range of 0.5 percent to 98 percent on the printed samples. The difference among the remaining plates was not appreciable. These same three plates exhibited the strongest line resolution of the printed samples as well.

The unexpected result of the study was that, from plate to print, most plates exhibited sharpening (dot loss) rather than dot gain.

Consultant Curt Thormodsgaard, who has had extensive personal experience testing such CTP and thermal plates, commented that “it’s next to impossible to match old printing with thermal plates. Best results come from generating new tone curves.”

Frank Gualtieri, GATF’s director of technical services and one of the thermal study team members, added: “Ink key zones must be assured of working properly because thermal plates are not providing dot gains.”

George Leyda, a GATF research fellow, remarked that he felt “there were no losers (among the plates tested).”

Eight thermal plate manufacturers submitted a total of 11 different plates to GATF for its first study in comparing various print-related characteristics. The detailed report is expected to be published in mid-March.

Attendees at the conference were in agreement that thermal plates offer the highest resolution of the currently available digital plates. The fact that almost every manufacturer is offering thermal upgrades to their platesetters further reinforced the common presumption here.

Computerized press makeready, computer-integrated manufacturing and a discussion of the Adobe Portable Document Format (PDF) were also part of the two-day agenda.

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