Product category:
Printing Pre-Press Systems and Materials (Repro, Platemakers, CTP, Workflow, Document Management, Design Software, etc.)
News Release from: Ghent PDF Workgroup | Subject: Specifications large format digital, screen print
Edited by the Printingtalk Editorial
Team on 08 February 2007
Large Format Digital And Screen Print
PDF Spec's
The Ghent PDF Workgroup (GWG) has announced four new GWG Specifications addressing two additional markets - large format digital printing and screen printing.
The Ghent PDF Workgroup (GWG) has announced four new GWG Specifications addressing two additional markets - large format digital printing and screen printing The specifications are claimed to answer the growing need for PDF best practices in these markets, which are rapidly moving to PDF workflows, said the organisation
This article was originally published on Printingtalk on 25 Aug 2008 at 8.00am (UK)
Related stories
Version 4 of GWG specifications gets a release
Graphic arts experts have come together to release version 4 (v4)of the Ghent Workgroup (GWG) specifications for automated workflow efficiency in a range of application and output environments.
Soft-proofing Ticket - The Easy Option
Ghent PDF Workgroup launch of the Soft-Proofing Ticket, an easy way for end-users to have additional, essential information about the approval conditions.
The four new free specifications are additions to the GWG 2005 v3 specifications offering best practices for PDF file exchange in graphic arts and publishing applications.
According to Andy Den Tandt, technical product manager for Enfocus and co-chair of the GWG specifications sub-committee: "As a group we are really pleased with the progress and speed with which we've collaborated and developed these best practice PDF specifications for practical production applications.
The goal of the Ghent PDF Workgroup is to make it easy to produce reliable digital documents that can be used from creation to final print production.
Further reading
New PDF Specifications For Printed Packaging
The Ghent PDF Workgroup (GWG), has launched its new GWG Packaging Specifications for PDF file exchange in printed packaging applications.
PDF University Explores Value Of Specifications
The value and use of Ghent PDF Workgroup (GWG) Specifications will be covered in PDF University sessions being hosted by Xplor International.
Job Ticket Stays With PDFs Right Up To Production
The Ghent PDF Workgroup (GWG) has made available the first in a series of Job Tickets to come from the group - Ad Ticket.
To accomplish this, the Ghent PDF Workgroup considers the entire workflow and all the steps that influence the final result." Nick Stevens, technical director of the SP Group, one of the largest screen and digital printers, including large format, in the UK, commented: "Customers are generally well informed regarding the specifications of the litho process, but quite often don't have an understanding of the requirements of screen or digital processes, therefore these new standards will help to deliver files appropriate to these production processes." The four new specifications added to the GWG release v3 2005 set address two new, rapidly expanding markets, those being large format digital printing - specialised high resolution print productions using screen rulings higher than 150 lines per inch (lpi) - 60 lines per centimetre - or using special screening technologies, such as FM and stochastic, or large format printing (where the pages are created at a fraction of the final output size).
Other applications include very high resolution (without downsampling) CMYK (CmykVeryHiRes_1v3) and CMYK+spot (SpotVeryHiRes_1v3).
In the standard GWG CMYK HiRes specifications, colour and grayscale images shall not be below 100 dots per inch (dpi) and should not be above 300dpi, said GWG.
That is common practice for many Hi Res printing applications using traditional screening with screen rulings up to 150lpi (60 lines per centimetre).
For special productions, the use of higher frequency screens, FM screening, stochastic screening, or a mix of some of those technologies may require higher image resolutions to result in the best possible, fine detail in print.
For such projects, GWG recommended using the specifications CmykVeryHiRes and SpotVeryHiRes.
Using those settings will leave the image resolution unchanged (with no downsampling during PDF creation and pre-flighting, for instance).
Image resolution for VeryHiRes applications may vary depending on the screening technology used, as well as on subject matter.
As a rule of thumb for traditional screening, it is recommended that image resolution should be 1.5 times to two times the screen resolution.
For alternative screening technologies (such as FM and stochastic) users may follow the instructions of their suppliers, or define the optimum image resolution by printing test targets.
For both graphical and industrial screen printing, using screen resolutions between 15lpi (six lines per centimetre) in outdoor up to 150lpi (60 l/cm) indoor.
Screening technology may vary from traditional screening (rounded and oval dot) to other screening technologies, such as FM and stochastic.
The new specifications added to the GWG v3 2005 set join the recently released GWG Packaging Specifications.
• Ghent PDF Workgroup: contact details and other news
• Email this article to a colleague
• Register for the free Printingtalk email newsletter
• Printingtalk Home Page
Search the Pro-Talk network of sites
