Details:
Summary:
The SNAP organization (Specifications for Newsprint Advertising Production) provides guidelines and recommendations for optimal reproduction on newsprint substrates using cold-set offset lithography web presses. � To assist the printing community to validate if new or augmented press equipment is capable of printing to the specification, SNAP publishes a "Lithographic Offset Press Acceptance Testing and Criteria for Acceptance" document that details:
Testing and press acceptance conditions
- Description of acceptance testing
- Suggested aim points and tolerances and
- Test forms and testing procedure
Controlled press testing was conducted on multiple cold-set newspaper presses using these procedures and an analysis is done to validate compliance of the empirical results with Item c: Suggested aim points and tolerances. � In addition to presenting the actual results of press acceptance tests, a statistical approach is utilized to identify standard errors and new tolerances for cyan, magenta, yellow and black densities across three production sequences:
- Cold Start (initial press startup with presets)
- Mid-Production Speed and
- Full Production Speed
Verification research is conducted with the test data set from two cold-set newspaper presses located in different locales. �Printed samples were collected during the press acceptance test run per the test protocol. �The test and protocol is designed to replicate daily print production conditions.
The analysis indicates that mean printed Status T optical density of the data set falls within the SNAP aim values recommended for reproduction on newsprint substrates using cold-set offset lithography web presses. � Additionally, a more reliable statistical approach that defines optimal press performance tolerances using standard error is provided as an addition to the +-0.05 Status T optical density tolerance currently published in the SNAP documents.
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