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IDProjectCategoryView StatusLast Update
0013368ScribusPDFpublic2015-09-26 20:56
Reporterkaspar Assigned Tojghali  
PrioritynormalSeveritymajorReproducibilityalways
Status closedResolutionno change required 
OSUbuntu 12.04.5 LTS 
Product Version1.4.5 
Summary0013368: Problem with "total ink density" parameter Scribus 1.4.5 generated PDF file
DescriptionI asked advice about scribus@lists.scribus.net mailing list, but got a recommendation to post the bug report.

I have a problem with "total ink density" parameter Scribus 1.4.5 generated PDF file.

Case A:
I use Scribus for making a cover for a book. Design is tiff file made with Gimp. I converted RGB file to CMYK file. The result of the command "identify -verbose cover-CMYK.tiff" is: "Total ink density: 270%" and "Profiles: Profile-icc: 1829087 bytes SC paper (ECI)". That is ok. If I add this file to Scribus and export to PDF/X-1a file, the result of "identify -verbose cover.pdf" is: "Total ink density: 400%" and "Profiles:" rows is not existing.

Case B:
I use Scribus for making the content of the book in grayscale. If I export this to PDF1.3 file the result of "identify -verbose book.pdf" is: "Total ink density: 400%" but should be "Total ink density: 270%".

The problem seems to be Scribus, not ICC profile. When I use ImageMagick (convert cover-RGB.tiff +profile icm -profile /usr/share/color/icc/AdobeRGB1998.icc -profile /usr/share/color/icc/SC_paper_eci.icc cover-CMYK.pdf) to make a PDF file, I get the result: "Total ink density: 296%".
Additional InformationAll files are here: https://failid.rammo.net/index.php/s/sVBqXXLYBgM1JBp
TagsNo tags attached.
PatchNo

Activities

jghali

2015-09-23 19:40

administrator   ~0036349

Last edited: 2015-09-23 19:42

There is no issue. The issue comes from an ImageMagick limitation vs prepress requirements. The 400% ink limit found by ImageMagick identify comes from PDF marks located outside of bleed zones, noticeably registration marks. Those marks use a special colors called registration color which by definition and for technical reason use 100% for each ink. In production, those 400% are not a problem because those marks are thin and outside the page.

PDF has a concept of page zones. The most important are the TrimBox and BleedBox which defines zones where elements which should be found in the final product appear. Those boxes are all defined by in PDF exported by Scribus. The area located between TrimBox and BleedBox is cut during the production process (with a small margin of error). The various marks are located outside these zones. ImageMagick "identify" scan also those elements while they could be avoided.

Fyi, Acrobat shows that the max ink coverage inside bleed box is 270% in both cases A and B.

jghali

2015-09-23 19:52

administrator   ~0036350

Additional info: professional preflight checkers such as Pitstop Pro consider elements position when checking for ink coverage. They are able to detect in which PDF page zone each element is located and are able to skip elements which are outside a specific page zone.

kriks

2015-09-24 13:15

reporter   ~0036360

Just a note: you can add "-define pdf:use-trimbox=true" to your identify command (before the filename), but it still doesn't gives the 270% (my result is 295.686%).
I don't know where the difference comes from.

Kunda

2015-09-24 13:18

updater   ~0036361

This should be documented somewhere. 'Fringe technical issues' or something.

Kunda

2015-09-26 20:56

updater   ~0036399

Closing.

Issue History

Date Modified Username Field Change
2015-09-23 17:46 kaspar New Issue
2015-09-23 19:40 jghali Note Added: 0036349
2015-09-23 19:40 jghali Status new => resolved
2015-09-23 19:40 jghali Resolution open => no change required
2015-09-23 19:40 jghali Assigned To => jghali
2015-09-23 19:42 jghali Note Edited: 0036349
2015-09-23 19:52 jghali Note Added: 0036350
2015-09-23 19:55 jghali Priority urgent => normal
2015-09-23 19:55 jghali Additional Information Updated
2015-09-24 13:15 kriks Note Added: 0036360
2015-09-24 13:18 Kunda Note Added: 0036361
2015-09-26 20:56 Kunda Note Added: 0036399
2015-09-26 20:56 Kunda Status resolved => closed