PDF Day France will be the first French-speaking event of the PDF Association, organised by our member ORPALIS. It will take place in Toulouse which is the home ground of Airbus and we are very happy that Airbus will present a case study around its usage of PDF in their document management environment!Electronic Document Conference: Call for Papers
Prospective presenters at the Electronic Document Conference 2019 are invited to submit high-quality original proposals for 25-minute presentations on subjects of interest to developers and technical product managers concerned with electronic document implementations.Have we passed ‘peak PDF’?
How do we gain insight into how users’ views of documents are shifting? Google Trends is an increasingly interesting source of high-level marketplace data. By aggregating Google’s search data over time, reporting a term’s popularity as compared with all other searches.Participating in the PDF Techniques Accessibility Summit
The PDF Techniques Accessibility Summit’s objective is to establish a broad-based understanding of how PDF files should be tagged for accessibilty. It’s an opportunity to focus on establishing a common set of examples of accessible PDF content, and identify best-practice when tagging difficult cases.Members supporting PDF features!
The typical adoption curve for PDF technologies until approximately 2007 tended to track with that of the original PDF developer. Since then the marketplace has shifted; it’s no longer clear that Adobe drivesPDF feature support worldwide. Accordingly, we are happy to report that adoption of PDF 2.0 continues apace, with new vendors announcing their support every month.
The aim of this article is to provide a compact overview on the subject of PDF/A and colors. More detailed information about this topic is available on the PDF/A Competence Centers website. Especially recommended is the Technical Note TN0002 – Color in PDF/A-1.
The article provides several user examples based on Adobe Acrobat 8 Professional. There are also numerous other PDF/A tools which are not mentioned here.
What makes PDF/A unique and special? The following items are important for long-term archiving:
The visual appearance should be guaranteed over a long period of time. In addition, it must be ensured that the PDF file can be (correctly) visually reproduced on any (including future!) output device.
In order to achieve this, all of the necessary resources must be embedded in the PDF file, for example text, vector graphics, images and fonts.
The colors must also be exactly defined. This is achieved by means of ICC-based colors and device colors with output intents.
There are numerous object types in PDF files that can be colored.
The category page objects includes images, vector graphics, text, Type3 fonts and patterns.
Comments / Annotations also include colored objects that one may not expect at first, for example form fields, digital signatures, links (visible borders) and of course the annotations themselves.
Device colors only describe a portion of an (undefined) color (for example 80% red, 80% green, 0% blue). Device colors result in varying colors when reproduced on different output devices. Even the color of the paper can have an influence.
Due to this, PDF files can look different according to the output device:
Laser color printer
The divers color ranges of the individual color spaces are responsible for these color variations. This can be demonstrated by using 3D-models:
AdobeRGB vs. sRGB
IsoCoated vs. IsoNewspaper
PDF works with the following color spaces:
Device dependent color spaces include RGB, CMYK and Grey.
Media-independent colors are CIELAb, the calibrated colors CalRGB and CalGray, as well as ICC-based colors (RGB, CMYK and Grey)
In addition, special colors can be found in PDF files, including spot colors, (for example pantone, HKS), DeviceN, separation, indexed colors as well as patterns.
This standard format is used to characterize the color properties from input devices (cameras, scanners), viewing devices (monitors) and finally output devices (color printers, print processes).
ICC profiles are defined by the International Color Consortium. There is also an ISO standard (ISO 15076). ICC profiles are used in PDF for defining ICC-based colors and as output intents (OutputIntent).
More information on this topic can be found on the International Color Consortium website.
Here, a device independent color definition is used for every object with help of an ICC profile. One has the possibility of embedding the definition when constructing the object (like in Photoshop) or allocating the color spaces in Distiller.
Note: not all applications support an integrated color management.
The characterization of all device colors is implemented using a single ICC profile (valid for the entire document). With PDF/A, the ICC profile of the output intent must always be embedded (a simple reference is not permitted).
All types of ICC profiles are possible in PDF/A:
With Acrobat 8.0 Professional one can select the desired OutputIntent during the conversion process, when PDF/A is created by means of Preflight.
In Acrobat Distiller 8.0 Professional, the OutputIntent can be identified when setting up the job options.
Note: Distiller 7.0 Professional creates non-conforming PDF/A files, because it uses provisional parameters only.
There are common standard profiles depending on the program or area of application.
Office files use sRGB (defined by Microsoft and HP).
Low-end cameras frequently work with sRGB, whereas high-end cameras often employ AdobeRGB.
As a general rule, graphics use the monitors profile or AdobeRGB.
When printing with the sheet-fed offset method, ISO coated V2 (ECI) and ISO Uncoated (ECI) are common profiles.
ISO WebCoated (ECI) or SWOP (in the USA) are usually applied with web-fed offset printing.
ISO Newspaper (IFRA) is a special profile for printing newspapers.
Output intent Device Gray Device RGB Device CMYK Calibrated ICC-based
Grayscale ? – – ?
RGB ? ? – ?
CMYK ? – ? ?
No output intent – – – ?
Offset and gravure profiles
By Stephan Jaeggi, PrePress-Consulting
Translated from the German original by Reeves & Partner GmbH