Ottawa PC Users' Group (OPCUG)


   Copyright and Usage

   Privacy Policy

   Contact Us


PDF-XChange Viewer, a further review
Part 1, How to Search an Image PDF<

by Micheline Johnson

PDF-XChange Viewer (PDFXCV) has already been reviewed by Alan German. This review looks at PDFXCV from a somewhat different viewpoint.

PDFXCV stops the execution of nefarious scripts from Virus's/trojans etc. with a feature called Data Execution Prevention (DEP). Installation of PDFXCV also installs Tracker Updater, pinned to the Start menu.

In the PDF security section of the Secunia 2015 Vulnerability Review,, subtitled: “A look at vulnerabilities in the 5 most popular PDF readers - Adobe Reader, Foxit Reader, PDFXChange Viewer, Sumatra PDF and Nitro PDF Reader,” Secunia noted that:

  • There were 43 known vulnerabilities in Adobe Reader, and that 32% of users left these unpatched.
  • There was 1 vulnerability in Foxit Reader.
  • There were no vulnerabilities in each of PDFXChange Viewer, Nitro PDF Reader and SumatraPDF.

Support comes in the form of a 209pp manual, available from the Download Now box or:

Adobe Reader download (v 2015.010.20056) is currently 81.57 MB. Foxit Reader download (v7.2.8.1124) is 38.2 MB. Tracker PDF-XChange Viewer download (v2.5.313.1) is 17.2 MB. Installed sizes of each are correspondingly larger.

IFilter is a plugin that allows Microsoft's search engines to index various file formats (such as documents, email attachments, database records, audio metadata etc.) so that they become searchable. Without an appropriate IFilter, contents of a file cannot be parsed and indexed by the search engine. iFilters are included in products such as Adobe Reader, PDFXCV, LibreOffice, Microsoft Office and OpenOffice. Tracker Software claim that their super-fast IFilter, (supplied FREE with all PDF-XChange Viewer installs) extracts and searches text from pages, document info (title, authors, subject etc.), comments, and bookmarks etc - faster than any competing IFilter product available!

PDFXCV has another great searchability feature, that which adds a text layer to an image PDF, by means of built-in OCR code, allowing an image based PDF to be searched, and the text to be extracted. Originally PDFs were generated from text documents, and were therefore searchable. Today, many if not most PDFs are just a collection of images, particularly those generated from copiers or scanners, and are therefore not searchable. Image based PDFs can be made searchable by means of the built-in OCR in PDFXCV.
The graphic at right, shows the OCR dialogue, which allows you to

  1. Select which pages of the open image PDF to OCR.

  2. Indicate what the primary language is. Built-in languages are English, French, German and Spanish. Other languages can be downloaded, see OCR Language Extensions.

  3. Choose the OCR accuracy (low, medium, high).

  4. Choose output type:

Preserve Original Content & Add Text Layer, or
Convert Page Content to Image only – Add Text as Layer.

A test document was made by scanning to PDF the print version of the December 2015 issue of the OPCUG newsletter (News 1512), using a Lexmark Genesis S815 scanner, thus producing an image PDF. This test document was opened in PDFXCV and then OCR’d on two computers: a cheap Celeron N2805 based Netbook running Windows 8.1, and a 1st generation Core i-7 desktop running Windows 7, each at low, medium and high recognition accuracy.



After OCRing this test image PDF, text became selectable and searchable. Search had no problem finding key words such as “Bob Johnson”, as shown above.
PDFXCV took 100s, 85s and 153s on Low, Medium and High Accuracy settings respectively to OCR this test PDF on the Netbook. It took 30s, 22s and 40s on Low, Medium and High Accuracy settings respectively to OCR it on the Desktop. It seems that Medium Accuracy has been optimized in that this setting was faster than that for Low Accuracy, on both the netbook and on the i-7 desktop.

Extracted text included typical OCR errors, but in spite of this, accuracy is sufficient for search to work in nearly all instances. To get a measure of the accuracy of the OCR engine, I selected all the text on page 1 of the OCR’d test PDF, copied and pasted it into Word (which shows suspect words underlined in red), and counted the suspect words. I counted 115, 20 and 60 OCR errors respectively for Low, Medium and High Accuracy settings, out of a total of about 700 words. Again, the performance of Medium Accuracy is better than that of High Accuracy, which suggests that more work on improving the Medium Accuracy setting has been done than on the other two accuracy settings. It is therefore recommended that you use the Medium Accuracy setting.

PDFXCV includes its own screen capture tool (as does Windows), see Snapshot Tool icon on the top toolbar. But a screen capture image is limited in resolution to that of your monitor. For example, when using the Windows snipping tool to capture page 40 of the manual, the image size was 666x954 pixels (93 kB). When p40 was exported using PDFXCV Export to Image, at 300 dpi, the image size was 2480x3508 pixels (601 kB).

Thus if you want higher resolution, you can export the original image(s) of any or all pages in the PDF to almost any image format, by going to

File | Export | Export to Image

The Export to Image dialog is shown at right.

Images from any or all of the PDF pages can be selected to be exported.

The choice of image types these images are to be saved as, can selected from BMP, PNG, GIF, PBM, PGM, PPM, JBIG2, JPEG2000, JPEG, WBMP, JNG, PCX, DCX, TGA, TIFF. Image resolution can be chosen from 72, 96, 100, 150, 300, 400, 600, 1200, and 2400 dpi.

PDF-XChange Viewer now includes a Windows shell extension to display thumbnails of PDF files in Windows Explorer. When using thumbnail mode view in Windows Explorer, thumbnails of the first page in a document are shown instead of standard PDF document icons when the folder is set to view small, medium, large, or extra-large icons.


In small and medium icon mode, these thumbnails are very low resolution. In large and extra-large icon modes, these thumbnails appear as shown above. The download file contains two installation files – one for the viewer itself and one for the Shell Extension for viewing thumbnails in Windows Explorer. Installation of this extension is optional, but you might miss if you don’t know it is there.

Bottom Line:

Tracker Software (incorporated in 1997) has its headquarters in Vancouver Island. The current version (2.5.0312.1) was released 2015-02-09. PDFXCV free downloads are available from the Download Now box at the top-right of its web page at, including

ZIP installer (32/64 bit), 17 MB (includes EXE installer, plus XML file for the Shell Extension for viewing thumbnails in Windows Explorer.)

Viewer Manual (PDF), 7 MB

EXE installer (32/64 bit), 17 MB

Portable version (ZIP), 8 MB

and more

For a more detailed version of this article, read it online at:,_a_further_review,_update_2016-02-01.pdf.


Originally published: April, 2016

top of page



Archived Reviews





The opinions expressed in these reviews
do not necessarily represent the views of the
Ottawa PC Users' Group or its members.