gImageReader Qt5 vs Qt6: Which Version Should You Download?

If you have visited our download page recently, you might have paused for a second. Unlike most software that just gives you a single “Download” button, gImageReader presents you with a choice: Qt5 or Qt6.

For the average user just wanting to scan a PDF, this is confusing. What is Qt? Is version 6 always better than version 5? Will I lose features if I pick the wrong one?

In this deep-dive comparison, we are going to strip away the developer jargon and explain exactly what these frameworks mean for your OCR experience. We will analyze the differences in performance, memory usage, and compatibility to help you make the right choice for your machine.

What is “Qt” and Why Does gImageReader Use It?

Before comparing numbers, let’s understand the technology. Qt (pronounced “cute”) is a powerful cross-platform framework used to build graphical user interfaces (GUIs).

gImageReader is simply a “face” for the Tesseract OCR engine. Tesseract itself has no windows, no buttons, and no menus—it lives in the command line. gImageReader uses Qt to draw the windows you see, handle your mouse clicks, and render the PDF pages on your screen.

Since gImageReader v3.4.x, the developer has started offering builds based on the newer Qt 6 library, while maintaining the older Qt 5 builds for compatibility. This transition is similar to moving from Windows 10 to Windows 11: everything looks mostly the same, but the “engine” under the hood has been completely overhauled.

Head-to-Head Comparison: The Specs

Why You Should Choose the Qt6 Version (Windows 10/11)

If your computer was bought in the last 5 years, the Qt6 build (found on our download page as gImageReader_3.4.3_qt6_x86_64.exe) is almost certainly the right choice for you. Here is why the upgrade matters more than you think.

1. The “Blurry Text” Fix: High-DPI Support

This is the single biggest advantage. In the older Qt5 version, if you used a 4K monitor or a laptop with a high-resolution display (like a Surface Pro or Dell XPS), gImageReader often looked blurry. The text was scaled up by Windows like a low-quality image.

2. Smoother PDF Rendering (Hardware Acceleration)

When you import a large PDF (say, a 500-page scanned book), gImageReader needs to render those pages on your screen.

• Qt5 relied heavily on older OpenGL drivers, which sometimes caused flickering or slow scrolling on modern graphics cards.
• Qt6 uses a new “Rendering Hardware Interface” (RHI). It can natively talk to DirectX 11/12 on Windows, Vulkan on Linux, and Metal on macOS.

In our tests, scrolling through a 100MB PDF file was noticeably smoother on the Qt6 build, with less “stuttering” when zooming in and out of pages.

3. Better Multi-Monitor Handling

Do you use a laptop connected to an external monitor? A common bug in Qt5 apps is that dragging the window from a 1080p screen to a 4K screen causes the interface to explode in size or become tiny.

Qt6 handles per-monitor DPI scaling much better. You can drag the gImageReader window between screens with different resolutions, and it will automatically adjust its scale factor on the fly without needing a restart.

When to Stick with Qt5 (The Legacy Option)

While newer is usually better, “newer” also means “more demanding”. The Qt Group (the developers behind the Qt framework) officially dropped support for Windows 7 and Windows 8.1 with the release of Qt 6.

The “Entry Point Not Found” Error

If you are on Windows 7 and you try to run the Qt6 version of gImageReader, nothing will happen. Or, you might see a scary-looking system error like this:

Also common are errors related to api-ms-win-core-path-l1-1-0.dll or simply a silent crash on startup.

Is the Qt5 Version “Worse”?

Not really. In terms of OCR accuracy, both versions use the exact same Tesseract 5 engine.

• You get the same LSTM neural network accuracy.
• You get the same spellchecker.
• You get the same export options (PDF, hOCR, Txt).

The only things you are missing are the High-DPI sharpness and the smoother scrolling we mentioned earlier. If you are on an older PC with a standard 1080p monitor, the Qt5 version will look and behave 99% identical to the new one. In fact, on older hardware with limited RAM (4GB or less), the Qt5 version might actually feel slightly snappier because it has lower overhead.

Bonus: Portable vs. Installer – Which is Better?

Once you’ve decided on Qt5 vs Qt6, you have one last choice: do you want the Installer (.exe) or the Portable (.zip) package?

The Installer (.exe)

This is the standard choice. It installs gImageReader into your Program Files directory, adds a shortcut to your Start Menu, and sets up the uninstaller.

• Pros: Integrated into system, easy to find, updates are easier to manage.
• Cons: Requires Administrator privileges to install.

The Portable Version (.zip)

This version is a self-contained folder. You download the ZIP, extract it, and run the executable inside. It does not write to the Windows Registry.

• Pros: Can run from a USB stick on any computer. Ideal for work or school computers where you don’t have Admin rights.
• Cons: You have to manually create your own desktop shortcut. You must remember where you extracted the folder.

Final Verdict: The Decision Matrix

Still unsure? Find your specific situation in the list below to see our recommended download.