BN Tech Virtual Scanner — FAQ
Frequently asked questions for end users of the BN Tech Virtual Scanner TWAIN Data Source.
FAQ
Q1. The TWAIN source list does not show BN Tech Virtual Scanner
- 32-bit apps require the 32-bit DS; 64-bit apps require the 64-bit DS.
- Verify
C:\Windows\twain_32\bntech\bntech_virtual_scanner.ds(or the 64-bit equivalent) exists. - Some apps cache the source list; restart the app.
Q2. Scan output has swapped red/blue channels
- This was fixed for Memory Transfer mode. Make sure you are running the latest DLL; file an issue if it still happens.
Q3. The settings UI does not appear
- The host app may have started with
ShowUI=FALSE; this is normal. - Verify the default browser launches; the DS serves the UI on a local HTTP port.
- Make sure
TWAIN_logo.pngandFreeImage.dllare in the same folder as the.ds— missing components prevent UI startup.
Q4. Every scan returns the same image
- The DS auto-advances alphabetically. With only one image the result repeats.
- Delete
%APPDATA%\bntech\images\info.jsonor add more images.
Q5. Install says "file in use"
- Close every app that has loaded the DS (XnView / Twack 32 / NAPS2 / Photoshop, …) and retry.
- A TWAIN DS is a DLL; it cannot be overwritten while loaded.
Q6. How do I force a UI language?
- Edit
%APPDATA%\bntech\config.inito setlanguage=en_USorlanguage=zh_CN, then restart the host app.
Q7. Host app crashes on large scans
- A4 at 600 DPI 24-bit is ~100 MB per image, plus the DIB copy. 32-bit apps hit the 2 GB address-space wall; drop to 300 DPI or use Gray for very large scans.
Q8. How do I verify both 32-bit and 64-bit work?
- 64-bit: use IrfanView 64 or NAPS2 64 → File → Acquire → check the source list.
- 32-bit: use Twack 32 or XnView (32-bit) → same path.
Feedback
If the FAQ above does not resolve your issue, please file an issue on the project repository and include: Windows version, host app name + version, DS bitness (32 / 64), a settings UI screenshot, or files under %APPDATA%\bntech\.
Email: tandge@gmail.com