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Rewrite PDF Links on the Fly

December 3rd, 2025

When you pair SetaPDF‑Stamper with PDF Ink, a whole new world of “smart PDFs” opens up. Imagine every external link inside a downloadable PDF guide instantly morphing into a personalized gateway—complete with affiliate codes, UTM tags, or a secret user token—without ever touching the original source file. With just a few lines of PHP, you can walk the document’s page tree, sniff out each PDF UriAction, and splice a custom query string onto the URL. We'll show you how.

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Small‑Biz Perseverance v. Big‑Corp Muscle – A WordPress Plugin Battle

November 4th, 2025

Why purchase software from an indie developer? Here we provide an insight into the "little guy's" fight for survival - and relevancy - in a market that favors big brands. This blog post details how PDF Ink has one-upped other PDF watermark plugins over the years and yet struggles to gain ground - from a unique *ethical* standpoint. Nevermind it has a ton more features and great support, ya-dee-ya... the playing field is not level!

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PDF Reader & Writer – A Friendly Guide to Keeping Your PDFs Healthy

July 20th, 2025

Why a PDF reader matters (even if you only want to add a watermark or a password) When you take an existing PDF—say, a customer invoice, a contract, or a product brochure—and want to modify it, the first step is to read the file into PHP memory. Another word for read is parse. The PDF is parsed into PHP memory. A PDF reader does exactly that: it parses the raw byte stream, builds an internal representation, and tries to make sense of the PDF syntax (objects, streams, cross‑reference tables, etc.). If you open any PDF in a plain‑text editor (TextEdit, BBEdit, Notepad…) you’ll see a mixture of human‑readable keywords (/Type, /Pages, /Resources) and binary blobs. […]

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Using Sample PDFs for Marketing & Search Engine Optimization

June 13th, 2025

Many content creators overlook the potential of using their PDF files to enhance visibility on search engines, not realizing that search engines will parse accessible PDF files for content. There's a whole untapped source of web content, right under your nose! At PDF Ink we spend a lot of time promoting PDF security, but sometimes PDF content can be too secure. If you are trying to generate leads or improve SEO, it might be time to share sample PDF files.

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Integrating SetaPDF-Stamper using PHP

January 23rd, 2025

Look ma! No WordPress required! In the documentation for PDF Ink, it is explained how to write a simple script to fire up the PDF Ink PHP library and stamp a PDF file. The library is written in such a way that it can be used without WordPress, and any one of six different PDF-manipulation library sets can be used. This is helpful when one set doesn’t work with a specific PDF, but another set might. As always, when PDF Ink fails for any specific PDF, the solution is to either attempt to repair the PDF — or upgrade to a better library, like SetaPDF-Stamper. The example in the documentation is for TCPDF/FPDF, so here […]

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PDF Embeds with Adobe SDK and PDFObject

December 22nd, 2024

Adobe SDK The JavaScript-based Adobe PDF Embed API allows us to embed PDF viewers, showing manipulated (encrypted/passworded and/or stamped) PDFs on our WordPress site using PDF Ink shortcodes. These embeds can be highly customized using filter hooks, becoming handsome and useful interfaces for your users. It is up to you and/or your developer to familiarize yourself with use of the Adobe SDK API and the Adobe SDK PDF appearance/function control options in order to customize your embeds further. Using a default PDF Ink embed shortcode with its defaults might be just fine for your purpose. But it isn’t too hard to customize using PHP. SDK parameters are filtered by PDF Ink in the following call: […]

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Adding Watermarks to PDFs with Layers

November 13th, 2024

PDFs with layers are a powerful tool with various applications, from architectural designs to GIS to sewing patterns. The ability to manipulate these PDF files without compromising their functionality is crucial for user experience, professional standards, and design integrity. PDF Ink with the SetaPDF-Stamper addon stands out by ensuring that layer, form and table-of-content functionality are preserved while adding watermarks and passwords to files. This makes PDF Ink the ideal choice for anyone who distributes on PDFs with advanced features.

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Bridging the Gap between PHP 5.3 and 8.2

August 4th, 2024

This week I got involved with maintaining the languishing TCPDF library on Github. Long overdue. Embarrassingly long overdue, since I’ve based one of my businesses on this open source gem for nearly ten years now. The author, Nicola Asuni, has been working for many years on a successor to TCPDF, but it is stalled… likely due to the usual reasons: life and cash. I can relate. I’ve been sitting on a huge WP plugin project for two years now, desperately trying to move it forward while life happens and I’m forced to prioritize support for my paying customers. A couple years ago an eager young programmer, William Desportes, hopped onto the TCPDF GitHub and made […]

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Shortcode for stamping Woo product variation

November 13th, 2023

Here is some PHP code for WordPress/WooCommerce which will make PDF Ink recognize TWO custom shortcodes in any watermark content: [VARIATION_DESC] and [VARIATION_NAME]. These translate to variation description and variation name, both aspects of a WooCommerce variable product. This code (everything above the dashed line) should get added anywhere in your functions.php file. If unsure where to put it, add it at the end of the file. You could also add the snippet using the WordPress plugin called “CODE SNIPPETS” (front and back end). This snippet development was sponsored by customer Michael. Thanks Michael! For reference (maybe for people migrating from WaterWoo to PDF Ink) here is a snippet which would have worked with WaterWoo:

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Comparing the Best PDF Watermarkers for WooCommerce

October 27th, 2023

When choosing between WooCommerce PDF Watermark and PDF Ink for watermarking and passwording PDFs, both plugins offer essential features but differ significantly. PDF Ink provides greater flexibility with customizable watermarks, allowing HTML tags, custom fonts, and multiple watermark locations. It supports advanced encryption options like AES and offers robust file management, including recycling previously watermarked PDFs. In contrast, WooCommerce PDF Watermark has limitations, such as fewer customization options and higher pricing. Read the full comparison!

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Invisible Watermarks and Other Ways to Protect Your PDFs

April 26th, 2023

PDFs are a fantastic way to share documents – they preserve formatting, are widely compatible, and can even be compressed for easy transmission. But what if that PDF contains confidential, sensitive or monetized information? The Portable Document Format (PDF) offers some security, which when stacked can be quite effective. These include: Invisible Watermarks: A Non-Visual Deterrent A watermark (also called a stamp) is usually a semi-transparent image or text stamped onto the background of each page in a document. The watermark can be your company logo, a confidential notice, or even a name or # copies authorized, or a copyright notice. While watermarks can’t completely prevent copying, they do make unauthorized distribution visually unappealing. Watermarks […]

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