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GdPicture components offer superior support for image acquisition from scanners, capture cards and digital cameras using TWAIN protocol in 32-bit and 64-bit mode.

With just a few lines of code, you will be able to start a single or a multiple image acquisition process using any TWAIN-compliant device, edit and save scanned documents to any destination such as a local/network machine, FTP site, web server, or database.

Intuitive low-level & high-level API are provided under .NET components and TWAIN ActiveX to let you negotiate all TWAIN 2.3 capabilities from any kind of WinForm, WPF or Web application.

60 Days Free Trial Download GdPicture.NET Now!

GdPicture.NET TWAIN SDK for Winform, WPF & Web applications development

Looking for cross browser-based document scanning support?

Our web toolkit DocuVieware provides all the necessary components to scan, edit, and save documents online. Check the live demo!


TWAIN scanning

The acquisition process requires three items: a scanner, a driver, and software. Drivers are the bridges that let the software communicate with the device through standardized APIs. TWAIN is an industry-standard API for image acquisition, strongly oriented toward scanners. Of the four different scanning protocols, TWAIN is the most widely adopted by the market. Supported by most operating systems (Windows, Mac OS, Linux/Unix), the protocol defines a set of options like resolution, color, scanning areas for flatbed scanners, and more. The TWAIN Working Group develops and maintains TWAIN since 1992.

Main TWAIN features of the SDK

  • Image source enumeration and selection.
  • Duplex scanning support.
  • 100% compatible with any Kofax VRS.
  • Handles 32-bit & 64-bit Data Sources.
  • Automatic Document Feeder (ADF) control.
  • Detect blank pages.
  • Number of image transfers negotiation.
  • Save & restore scanner configuration from file.
  • Image scanning attributes control, such as color-depth, resolution, brightness, contrast, size and more.
  • Detect & read barcode symbols, including Code 39/128/93, EAN-8/13, PostNet, PDF417, 2 of 5 Matrix and many others.
  • Acquire images to multiple formats, including PDF/A, PDF-OCR, encrypted PDF, Multi-page TIFF, JPEG, JPEG 2000, JBIG2, GIF, PNG and EXR.
  • Acquire images to an FTP or HTTP server.
  • Fully compatible with CITRIX systems and Windows Terminal Services*
  • Plus many more features that your scanner can support!

GdPicture - Twain SDK


Reliable technology

Reliable technology

API built on top of the best document imaging SDK of the market, taking benefit of more than 15 years of continuous research focused on innovation. Support for unstable TWAIN drivers thanks to continuous device diagnosing.

Reduced Time to Market

Reduced Time to Market

Add the advanced post processing features provided by the GdPicture.NET toolkit to your scanning application: PDF, OCR, formats conversion & document imaging SDK. Reduce the learning curve by using the same technology on different platforms.

Continuous Development and Delivery

Continuous Development and Delivery

To provide you with the latest technologies and an always up-to-date SDK, we publish weekly releases. Check our version history page and subscribe to our developer newsletter to learn more about the new features and improvements.

Universal scanning SDK

Universal scanning SDK

GdPicture.NET scanning SDK is compatible with the two most used scanning protocols, TWAIN and WIA. Acquisition from all types of scanner devices and digital cameras is possible with support for both 32 and 64bits.

Web scanning SDK with DocuVieware

  • TWAIN acquisition via the dedicated scanning snap-in. 0 configuration required.
  • TWAIN acquisition via the dialog window triggered by a dedicated toolbar button.
  • High & low-level API sets to customize any acquisition process entirely.
  • Communicate with 32-bit & 64-bit TWAIN devices.
  • All acquisition options are supported via the device driver user interface or using a dedicated TWAIN JavaScript API.
  • Adaptive compression mechanism.
  • High-volume document scanning.
  • Support for any transfer mode of the TWAIN specification that automatically selects the version with the best user experience based on the system resources available.
  • Save scanned documents as PDF/A or TIFF images by default.
  • Advanced document clean-up features.
  • Working flawlessly with all Windows browsers.
  • Preview scanned pages with intuitive zooming, rotating & page reorganizing tools.
  • Support for low bandwidth with fault-tolerance mechanisms.

How to use the live demo?

TWAIN acquisition can be made from the dedicated snap-in or a dialog window triggered by a dedicated toolbar button.

When launching DocuVieware for the first time, the viewer will require the installation of a small software to connect to the TWAIN devices. It is a one-time step, and once it has been installed, it is silently started with Windows.

DocuVieware will then be able to trigger the device driver window so you can choose the acquisition settings you need.

Learn more about TWAIN web-scanning on the DocuVieware website.



When should I used WIA over TWAIN?


WIA (Microsoft Windows Image Acquisition) API is standardized for acquiring digital images from devices that are primarily used to capture still images and for managing these devices. WIA is a COM interface, very different from but overlapping with TWAIN.

Compared to TWAIN, WIA offers much better support for digital cameras and much less sophisticated support for scanners.

There are a few other parameters to keep in mind:

  • support for scanners with ADF (Automatic Document Feeder) is much more robust with TWAIN.
  • WIA uses a common dialog for all devices.
  • TWAIN uses a dialog created by the device manufacturer, providing more options and custom capabilities for each device.
  • TWAIN has three transfer modes (Native, Memory, File) while WIA has two (Memory, File).
  • Most TWAIN sources save the settings of the previous scan, while WIA does not.
  • Duplex scanning mode offers better support in TWAIN (each side can be saved with different options) with WIA uses the same settings for both sides.

Check our WIA scanning page for more features and functionalities.


Are there other scanning protocols?


There are four scanning protocols currently used by the market:

Here is a chart that synthesizes the different features of each protocol:

Adoption by the market very high high low low
Developed by TWAIN Working Group Microsoft Pixel Translations (then EMC Corporation's Captiva Software). Now owned by OpenText SANE open-source project
Digital camera support high very high low very low
Supported OS Windows, Mac OS, Linux/Unix Windows Windows Linux/Unix
Licensing LGPL (Data Source Manager only) - free proprietary - free proprietary - commercial open source
Specification TWAIN specification WIA specification ISIS specification SANE specification


I want to test your library, but I don’t have a scanner


If you don’t have a physical TWAIN scanner to test the SDK, you can download and use a virtual scanner (32 & 64-bit) here.

How to use

Download and install GdPicture.NET package from here.

  • You will be able to find a compiled demo application in
    [Install directory] \Samples\Bin\PaperScan.exe
  • You will be able to find C# and VB.NET demo applications including source code in
    [Install directory] \Samples\WinForm\ (see TWAIN Scanning app.).
  • You will find other code snippets within the online reference guide found here GdPicture.NET Guides
  • You can find some discussions about TWAIN in the dedicated section of our community forums.

Check our other Scanning technologies

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