PDF

Pdf file format

Worldwide standard

The Portable Document Format (PDF) is a file format developed by the company of Adobe Systems in 1993. It is being used to save documents independently from the software, hardware or the operation system on which they were created, as well as the displaying device. The PDF files can contain text, images, as well as interactive forms, videos, animations, 3D graphics, sound tracks and digital signatures, with the primary target of the format to ensure that the document is visible the same way on any device. There are free available viewers for many platforms for the format. Some content types (like interactive forms, 3D graphics, videos, sound), however, are not supported by many PDF viewers and the documents are not displayed completely (with an alert on unsupported functionality) or only the supported parts of the documents are viewed. The best known viewer is the viewer of the company of Adobe - Adobe Reader freeware.

The ADOBE PDF file is divided into several continuous blocks. On the page, objects are marked as ""obj"", annotations as ""Annot"". The dimensions of the objects are stated in two dimensions (""[ x y ]""). The PDF format is coded in English terms (in words) and abbreviations. The text itself is coded similarly to the RTF format. This means that - for example - to support the national alphabet characters, the character of "á" is coded as " / 160".

This file format supports various types of coding and content protection (e.g. against text and content copying, printing, editing, adding comments etc.) and various types of image compressions.
 

PDF usage

PDF usage

Since its beginnings, PDF was primarily used as a printing format. The formal preparation for the printing (instructions for the printer) or accurate copy of the printed form.

Today, printing accuracy, independence from the end device and multi-platform are basic attributes of every PDF implementation in archives, workflows, and document exchanges.

During the years, PDF evolved from the simple need of accurate printing representation to a complex solution, offering:

> accurate colour representation, adding ICC of colour profiles, inserted fonts and transparent models

> cooperation option, using comments and annotations

> web optimising, adding jp2 and fast web view

> interactive variable data by adding forms and XTA

> dynamics by adding JavaScript and multimedia

> meta data model which grew to complex content tagging

> 3D models and GPS information

All these areas change constantly. The biggest advantage of the PDF format is that all the options are combined in one single solution. There are only few limitations, which can be, however, bypassed by adding own concept, as PDF allows private data and structures.

Every PDF based solution usually starts with the question: ""What exactly do we need to do with the documents?"" Usually, PDF proves to be the right answer.

PDF is being used at publishing documents, articles or books. The interactive and intelligent digital forms which take care of data collection or making it possible to print the forms and fill in the data manually.

The digital invoices signed by secured e-signature, containing data for automatic processing (ZUGFeRD), accounting statements, signed and submitted to the tax office, scanned and OCR processed received mail - this can all be done using automated accounting.

Digital file and several interacting documents in various formats in one PDF on one place.

Protection of documents from changes and content extraction to sophisticated DRM solutions which allow selling, renting or lending the documents.

Archiving is a separate chapter. PDF documents are predestined for long-term archiving. In archives, libraries or at communication with authorities, special PDF types are required.

Thanks to the accurate viewing model and qualities like 3D and interactivity, technical documentation is designed to be saved in PDF.
 

History of the PDF

History of the PDF

The Portable Document Format (PDF) is a file format developed by the company of Adobe Systems in 1993. In the next 15 years, it was revised 7 times. The company of Adobe released it for the needs of the International Standards Organization (ISO) in 2006. Since then, it has been managed by the PDF Association as the technical standard of ISO 32000. The original idea was digital replacement of paper in a form which would guarantee the best possible data viewing, independent from the hardware and software. During the years, PDF became an inseparable part of most digital archives and the standard of work with the digital documents. Approximately 80% of the online content (except the HTML pages) is stored in the PDF format. The created documents are being directly generated as PDF. But documents created in their paper form (old scanned documents, books, print materials etc.) are being converted into PDF, too.

PDF is a widely recognized universal platform, being the answer to all ""document"" problems of the modern online world.

During the revisions, the format has been adjusted to the needs of the individual segments of industry. Today, it can do much more than replacing office paper. It contains interactive elements, forms, data, multimedia objects, 3D models, or maps with exact tools to measure distances. It takes care of content securing, with the documents being able to be signed digitally or using security certificates. The useful annotation tools allow cooperation of whole teams.

In 1993, only one app was available to work with the PDF - Adobe Reader. Today, there are many PDF viewers, services and apps on the market. Creating a PDF document is considered a necessity of every app and viewing it is a must for every device - similarly to viewing images or text document.

The tool selection depends on the problems ou are trying to solve, the platforms you need to support and the available budget.

PDF and ISO standards

PDF and ISO standards

Releasing the PDF specifications by Adobe in favour of the ISO organisation provide the necessary prerequisite of creating open standards, increasing the credibility of the format. This way, the PDF meets also the legislative requirements.

The PDF association is an association of experts and technological leaders (in 2016, the association has had 200 members). The association members are well-known companies, like Adobe Inc., Hewlett Packard, as well as individual members from various industries. Thus, the focus is very wide and ISO standards based on PDF are being established, becoming successful in segments where they are ordered by the state authorities or regulatory bodies as mandatory.

The PDF (ISO 32000) standard describes PDF as general digital format. It forms the basis for all other standards. It has been reviewed twice and currently (in 2016), the biggest update of it is being prepared. It is based on PDF v1.7.

The PDF/A (ISO 19005) describes the sub-group of PDF designed for archiving. It ensures that PDF created according to the PDF/A allows interpreting the document clearly without depending on external sources. Today, there are several independent standards, introducing various implementation levels (PDF/A-1, PDF/A-2, PDF/A-3 at the levels of b (basic), u (unicode), and a (accessibility).

The PDF/UA (ISO 14289) is aiming on creating documents which are generally accessible. Simply said - they must be available also for the visually handicapped. The ability to create such document is required by WGAC 2.0, Section 508 etc. and it is important for automated content processing. PDF/UA means that the document carries the information on logical structure, image descriptions, headings, table definitions etc.

The PDF/E (ISO 24571-1) adds features necessary for machinery, construction, and production segments, as well as preparing plans, technical drawings and maps. It can store 3D models or GPS coordinates and using JAVASCRIPT, it allows interactive work in the PDF viewer.

The PDF/X (ISO 15930) deals with printing and preparation. It contains the sub-group of PDF elements and features which ensure that the file goes through all the phases of industrial preparation and printing without the need of changes, ensuring the quality of pring and anticipation of the results right from the input phase. It is available at various implementation levels.

The PDF/VT (ISO 16612-1) is designed for printing variable data. It is based on PDF/X to ensure printing quality, but contains mechanisms to ensure right filling in of variable data into document templates- It is being used for transaction printing in segments like banking, insurance, telecommunications etc..

Using standards ensures clear protocol among the individual institutions, as well as program modules. Therefore, the standards change and adjust to new trends and needs. As an example, we can name the PDF/R standard, which is being created based on the initiative of scanner producers under the label of TWAIN in cooperation with the PDF Association. It aims to create a format which would be generated by the device itself (scanner, camera, or mobile).