This settings panel allows for the upload of your own TTF font files. Before we dive into that, let’s talk about font use for a second.
Font Use
The Helvetica, Times Roman and Courier, Symbol and Zapf-Dingbats fonts included with PDF Ink arrive with Windows-1252 encoding. If you want to use one of these fonts but need different sub-setting, you would need to find/create those font files yourself (TTF) and use the font uploader in the plugin to add them.
There are various fonts included with TCPDF which are generously subsetted. Select the “Deja Vu,” “AE Furat,” “AE Al Arabiya,” “M Sung,” “Kozmin Pro,” or “Kozgo Pro” font in the Frontend/Sandbox Settings panels if your language uses accent characters. To see if your language will be watermark-able with the Deja Vu font, view this chart. Select Furat for Arabic script, or M Sung for Chinese, Kozmin or Kozgo for Japanese. Right to Left (RTL) watermarking is possible with TCPDF.
A primary reason watermarks do not show up, or shows up as question marks or empty boxes, is when the watermark contains special characters but a font which doesn’t support those characters is in use. Good reason to add your own subsetted font!
PDF Ink Font Uploader
You can add fonts to PDF Ink with a click. Adding a font subsetted correctly for the needs of your site and/or PDFs can not only make your PDFs easier to read, but can save a lot of PHP memory, too.
Visiting the “Font” settings page, you will see an uploader similar to the native WordPress file uploader. You can either click to upload files, or drag files (one at a time) into the uploader area marked by dashed lines.

In order for the font file to successfully be added to PDF Ink, it must be a TTF (TrueType font) file, and it must not be locked under license. Some TTF files may be rejected – it is up to you to figure out why based on error messages you may encounter, or find an alternative font to use. Once you get a “successfully added” message, your font will be available as a selections in the Frontend & Sandbox settings, and you can stamp with it. Note: if you are using SetaPDF Stamper, font licensing checks are done later and might fail during stamping – so test before deployment!
Added fonts just not working? First make sure the mbstring PHP extension is enabled on your server (ask your host if you are not sure how to do this). Beyond this what we can suggest is, try a different font!