Category Archives: PDF tips

New HTML5 service for online secure PDF viewing

Our online PDF viewer has just got better, faster and simpler to use, with even more security options. Examples of the new facilities are available via our Managed Online services page or simply click on the image below to see how this document looks within the secure PDF viewer – within your browser, on any device you like, with no software installations or downloads!

Adobe PDF print security is not secure at all!

Many people use the tools in Adobe Acrobat and related software (such as PDF exporting from MS Word) to add basic security features to their files. One such facility frequently required is protection against printing – essentially this disables the print menu and toolbar icon in Adobe reader and other Adobe products that display PDFs.

However, for some time now Adobe have recognized that this feature is not secure, because it is not part of PDF standards and other PDF reader providers do not implement this Adobe-specific feature. Indeed, Adobe Acrobat now displays a warning message to this effect (as shown below). For example, an Adobe print-protected PDF can be opened in Javelin for Windows and printed, with no problem at all! However, using the Print protection in our Drumlin PDF publishing software does provide such facilities, as the secured file is only readable using Javelin PDF readers (after authorization). Drumlin protects against printing of PDFs when you want to fully protect your PDF in this way, but also allows you to enable printing but restrict such printing to physical devices and specified numbers of pages.


Managed Services: Adding BUY NOW and ADD TO CART buttons

The Managed Services PDF Publishing facility we offer provides a web-based catalog ordering capability with Add to Cart or Buy Now buttons built into the online ordering pages. A full page examples can be seen at:

If required, these buttons can be placed on the publisher’s own website in order to provide a seamless user experience, optionally with the payment process etc being from the publishers own PayPal account. The result is still automated processing using our servers, so is essentially the same as linking to a catalog page on our managed services site. Other pages used in the process, such as the tailored email template and download template page, remain on our site and are managed by us on your behalf/with your branding/name etc..

Buttons such as these are created using simple HTML commands that look like: <form> a series of instructions… </form>. An example is:

If you click this button it will place a real order for a secure document (in this case a legal guide for US Law Students). In this example we have used the TEXT tab in the WordPress editor (as opposed to the VISUAL tab) to enter the HTML code that creates the button.

Some other points about this approach are noteworthy:

  1. Helpful information and guidance is needed to ensure that purchasers understand what technology platforms are supported (and maybe which are not supported) and whether or not printing of the item is permitted – our sample catalog pages all include this, so can be copied as examples
  2. If you do decide you would like buttons on your own site rather than ours we need to know this so we can ensure that customers return to your site rather than ours for additional orders etc – we would need to provide the button code for you, to ensure it is correct and has been tested on our servers first
  3. If we provide a managed service for a flat rate fee rather than a flat rate plus commission charge, you can be the recipient of the payments made directly rather than via us. Such payments have no commission deducted and appear directly into your PayPal account. In this case the PayPal payment receipt will be sent to you rather than us. You set the price and you are the contracting party for payment and any local sales tax/VAT computations and reporting.

For more information and advice on Managed Service PDF publishing please contact us

PDF Printing

It is often the case that PDFs are distributed without really thinking about protecting them against printing. Quite often people will add basic protection against copying and editing using the tools provided in Adobe Acrobat or similar software (see further, below), but files that are not protected against printing or do not control the printing process, can easily be copied, scanned (including to PDF with OCR) and onward distributed.

Pros and Cons of PDFs

There is a lot to be said for the humble PDF. It allows us to share documents easily across multiple platforms, preserving everything from our intended layout, to the correct page order, to our chosen font size and style. However, as noted above, standard PDFs are not protected against the editing or copying of content, nor from printing.

Using the Tools facility in Adobe Acrobat it is possible to add various forms of content protection. These include protection against copying, editing and printing. Date/time-based protection is not provided.

However, these facilities are specific to the Adobe PDF technology and can be bypassed by widely available software that implements decryption, memory-scraping and screen-scraping. Perhaps more importantly they do not provide protection against copying entire documents by simply forwarding these to third parties.

Knowing When to Secure PDFs against Printing

It goes without saying that printing sensitive information carries a significant security risk. Whether this be internally within your company, such as staff payroll documents, contracts, financial statements, or marketing plans, or externally when printing is outsourced. Securing against printing is an ideal way of limiting the unauthorized views of your documents. There may be other benefits, such as managing costs and meeting environmental objectives.

Protecting PDFs

For real protection of PDFs they need to be encrypted and have controls or permissions associated with them. Various tools exist for protecting PDFs. Many PC users, for example, have Microsoft Office as their main document creation facility, As with all current MS Office applications, the File menu, Export facility enables you to save the current document as a PDF. This includes on Options form, as illustrated below,which includes an option to encrypt the document with a password. This provides a level of security against opening the document – the saved document will only open in Adobe Reader if the correct password is entered. Note that this provides no protection otherwise, i.e. printing etc are still permitted.


If Adobe Acrobat is installed on the same computer as above, it will automatically appear as an option on the File menu in MS Office applications as “Save as Adobe PDF”. In this case a different form is displayed, with more security facilities (see below). This is where you can see the options to control for printing (and for editing/copying etc.). The default settings are shown. As can be seen, in addition to the Open document password control there is a second password protected Permissions section.


Digital Rights Management protection

The protection mechanism above works quite well, especially for documents that are not particularly sensitive or high value. There are two main problems with the above approaches however. The first problem is that the document can still be sent to anyone, anywhere in the world, and viewed and copied any number of times. The second problem is that the security applied can be removed in many cases, or simply ignored by using a different PDF reader that does not adhere to Adobe’s settings. The solution to both problems is to apply digital rights management (DRM) controls to the document. In this case the steps are:

  1. create a standard PDF with no special settings
  2. use a special program to encrypt and add security permissions to the file, such as print controls
  3. make the file available to the target user(s) via email, web download etc together with details of how they can open and view the secured document
  4. the target user(s) open the document using a PDF reader (general a free PDF reader provided by the DRM service operator). The document will only open if additional security checks are passed, in all cases requiring a local or wide area network connection, typically to an in-network DRM service. This all happens in 1-2 seconds and includes centralized logging of the events so that actions may be tracked

For more information on providing print security and other DRM-enabled facilities, please contact us

PDF form filling

Today’s question, which we are asked frequently, is “is it possible to have interactive form-filling in a secure PDF?” Here is our immediate response:

The brief answer is “no” – in fact this is a particularly problematic area where a document is encrypted, as “by definition” it cannot be amended because that would require decryption, modification of the document, and then re-encryption… which for truly secure offline documents is not possible. However, less secure solutions may be able to do this, and systems that interact with web-based facilities may also be able to do it. If you have an interactive PDF the probability is that it was produced using Adobe software, and their interaction and processing facilities are, in large measure, proprietary, so the main response would be “use Adobe reader/an Adobe-based solution” for those parts of the application that you need form-filling etc. This could mean separating a PDF into two parts, for example a secure document that was designed simply for reading etc, and some interactive forms that go with it and are essentially unprotected. Another option is to have a secure document but permit limited printing of forms – we have customers who do this, for example for medical interviews and assessments. Another option is to provide the solution entirely “on line” and have interactive forms provided programmatically and/or via standard tools such as flash or html5, or a forms builder. For Adobe’s core offerings in this area see:

PDF Print scaling

In previous posts we have commented on handling PDFs that have large page sizes. The question of how to print such pages frequently arises, so an update on our earlier discussion would seem to be timely. The first observation to make is that most consumers can only print A4 or US Letter paper sizes … less than 10% will have printers capable of handling larger formats, at least, that will the case at home – most offices have a wider range and print shops can handle a very large range of page sizes.

Typically a PDF reader (from Adobe or elsewhere) will re-scale any oversized PDF document to “best fit” the page size supported by the default print device. The re-scaling results may or may not be satisfactory and may vary by printer type, paper etc. In order to be sure of the end results, a simple option is to re-scale the source PDF. Then, when the end user prints the document, there is no re-scaling required and the results are exactly as you expect. If you want the user to be able to see the resulting printout in a larger format, all they then need to do is to photocopy it with a setting to enlarge the document to their preferred size. However…

… for documents that are 2+ times the size of standard paper sizes and/or require very precise scaling (e.g. dress patterns), this still leaves a major issue – re-scaling may be undesirable and/or unreadable. The solutions in this case are either: (i) offer an on-demand in-network print service, with delivery to the customer by post; (ii) offer pre-printed copies of selected documents that are over-sized, e.g. posters, newspapers, technical drawings, dress patterns etc; or (iii) permit the user to have the source PDF printed by a suitable (approved) print shop. Option (iii) is only possible if the source PDF is made available to the print shop and meets their requirements (i.e. a completely unsecured PDF) – in most cases using export settings (e.g. from InDesign) specifying that the output PDF is designed for print production will produce satisfactory results. The key variables are resolution (which must be 300dpi or greater), embedded fonts (to ensure the end result looks correct/uses the correct fonts), and sufficient bleed (2-3mm) to ensure pages can be trimmed to size where necessary. For most conventional documents the trim issue will not present problems. For precision printed documents (e.g. technical drawing to scale, patterns to be cut out) option (ii) is the only practical solution.

Secure PDF Printing

One of the security features many PDF publishers want to see is control over printing of their PDFs. This turns out to be rather more complicated than it might seem at first. Essentially there are two main options: (i) do not allow printing of any kind; and (ii) allow printing subject to some restrictions. The first option is the most common situation, and applies to many different types of document, especially ebooks. It is relatively easy to handle by not providing print facilities in the reader software or by disabling such facilities if they exist. In the case of standard (Adobe-style) PDFs this can be defined via the Security settings options in Adobe Acrobat. But remember that non-Adobe PDF readers may not respect these settings (i.e. ignore them with the result that the file is not actually secured at all) or may be subject to breach if the security settings are attacked using widely available software.

The second option has many variants, and these have become more complicated in the last 2-3 years. This is due to the rise of printers that are indirectly linked to the PC or Mac or other device, so may or may not appear to be real, physical devices… often they appear as WiFi “air” printers or in-network print server software packages. In general PDF publishers who permit printing wish to limit some aspects of this facility, such as:

(i) never allow printing to PDF or Image virtual printers
(ii) only print to local devices
(iii) only permit printing a certain number of times
(iv) only permit printing of a certain number of pages
(v) include an intelligent (user/computer/date/file-specific) watermark on some or all pages

This functionality has been supported as standard in  Javelin PDF readers for a long time, but the rise of the printer-that-is-not-obviously-a-printer has led to problems, especially with requirement (i). Within Drumlin v6 and the matching Javelin releases, this issue is handled by selecting the “Relaxed printing” flag in the Permissions form when creating a secure PDF. This flag uses a less strict algorithm than is the standard ‘strict’ version, with the result that the newer devices should be accepted as valid printers. If a warning message “Error -30” is issued it means that currently the Javelin reader being used cannot recognize the print device as valid – email us with full details (printer/print software Make, Model, version etc) and we will ensure it is included in our “Relaxed printing” facility.

Adobe and Drumlin PDF Watermarking – static and dynamic watermarks

PDF files can be protected from unauthorized copying in multiple ways. One of these is by the inclusion of watermarking, which itself comes in many variants.

Static watermarks

The first is the pre-loaded static watermark. If watermarks are added statically they are generally created by using a tool such as Adobe Acrobat or Infix to create an additional foreground or background item on some or all pages of a PDF. The screenshot below illustrates this, and as can be seen, the text entered appears on the selected page – here as a simple text string, in the color, size and orientation selected. Adobe Acrobat is very flexible in providing options for statically added watermarks of this type. Once added the PDF must be saved, so that the additional content form a permanent part of the PDF file itself. If this file is then protected, using Adobe’s standard security facilities, preferably with a longish password (8+ alpha-numerics) then the watermarking will have a reasonable level of protection against removal. Note that the watermark can contain any statically defined information you wish, so can be generic, e.g. “(c) My Company, 2013”, or “!This file has been issued to Mr A B Johnson of XYZ Inc – no copying of this file is permitted”

Dynamic watermarks

The second approach is the use of dynamic watermarking. As with static watermarking a dynamic watermark can contain static text, such as “(c) My Company 2013”, but that misses the real value of such facilities. The main feature of a dynamic watermark is that it includes information generated at the moment of display or printing, which includes end user or other information that makes the file “unique” and identifiable.

In the example below there are both static and dynamic watermarks included. The static watermark has been added to the source document using Adobe Acrobat – in this case it has been placed at a diagonal across the text in such as way as to extend across the page but with minimal interference with the text. The dynamic watermark, created using Drumlin, is shown at the foot of the page, and includes information about the file displayed (the filename itself), plus information that identifies the user (via the partially displayed code), the device on which the document is displayed, the date and other information. This  information is dynamically generated when the file is displayed and is overlaid onto this viewable screen window rather than embedded in the document. This means that when the page is zoomed in or out, the dynamic watermark is always displayed in front of the viewable area. This provides an added level of protection for the document against screen capture that is now a standard feature of many operating systems and hardware devices (e.g. a built in feature of Android and iPAD mobile devices). There are also a range of server-driven tools and PDF security products (e.g. those from Adobe, Vitrium, Foxit and others) that will automatically stamp or watermark PDF files that are downloaded.

How to edit your PDFs – we review the Infix PDF editor

I recently stumbled across the Infix PDF editor, from Iceni Technology (pronounced eye-seen-ee apparently, an ancient tribe from East Anglia), Anyway, it is a great piece of software for editing and augmenting PDFs, at a very good price (much cheaper than Adobe Acrobat, and with more powerful editing functionality). Essentially Infix is a wysiwyg editor for PDFs. It understands the mysterious and convoluted structure of PDFs and their many variants, so you can directly edit on-screen, very much as you would in Word or InDesign. The big difference is that you can amend the PDF output without necessarily having the source file from which it was created. You can even do really tricky things like trying to re-create the source file, or translate the PDF into other languages. Furthermore, you can augment existing PDFs with features like Adobe-style security, navigation trees, hyperlinks, annotations and more.

The screenshot below provides a glimpse of the functionality, where we have selected a text box to amend and added redaction to a section of text. A VERY brief summary of some of the key features that we like include:

  • wysiwyg editing of text blocks
  • merging multiple PDFs
  • extracting pages from PDFs
  • exporting pages to text, html, epub and rtf
  • adding redaction (example shown below)
  • adding bookmarks
  • adding static watermarks, including lots of built-in watermarks

For more details on Infix, please click here

PDF with very large page sizes

Most PDF files are created from source material that is either generated in some form of Office software, like MS Office Word or Powerpoint, OpenOffice etc, or from a publishing system like Quark or InDesign. In almost all instances the underlying page size or sizes used are A4/US letter or smaller, in a fixed orientation (portrait or landscape). However, for files that are generated from graphics (drawing/design) packages or engineering systems, or from large-format old documents that have been scanned in, there is an often an issue with the page size.

In general, electronic display of documents on tablet devices is best handled with a relatively small underlying page size and/or the use of larger fonts. A5/half US Letter gives excellent results on most devices, and conversely, larger than A4/US Letter tends to result in files that cannot be read without zooming in on the page. Typically zooming-in makes reading the whole document/seeing the whole picture difficult and if printing is permitted (which in many cases it is not of course) then issues arise with print scaling which may prove unsurmountable. Zooming into very large pages (which is effectively an image zoom operation) is computationally demanding and may be slow or even impossible after a specific level of zooming on some devices (i.e. the software restricts the total zoom level owing to memory management or processing issues on the device).

There are a couple of solutions to these problems:

Scaling the source material: if the source material is a scanned image or a graphic, then the output PDF file created can be scaled to a selected underlying page size, e.g. A4/US Letter. This scaling can take place as part of the PDF file creation or, for image data, scaling can be carried out in the source application or image editor prior to printing to PDF. Obviously a scaled image may well be unreadable at the reduced size and/or may lose resolution in the scaling process, so a second option is worth considering.

Tiling the source material: instead of creating a single very large page a series of standard-sized pages can be created, with the large page spread across multiple standard-sized pages. This can be done in two ways – the source program may allow the output page size to be specified (e.g. via a Page Setup option) prior to creating the PDF file, so they resulting PDF is spread across several pages. Alternatively, and in many cases as a preferable option, the PDF can be generated with large page sizes and then the pages can be tiled using the tiling facility in Adobe Acrobat, as shown below. Typically the tiling process generates output for printing on a standard printer – i.e. one that handles pages up to A4/US Letter in size, which is the most common use for this facility, but you can specify the output as a PDF, and then a new PDF with tiled pages will be generated. An example can be seen: here…. Note that in this example I have specified a 10mm overlap which tells Adobe Acrobat to overlap the output pages and to include trim marks in the margins so it is easy to see how the pages fit together, and if printing is permitted, how to print and assemble a full-sized page from the tiled elements.