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Forcing image document conversion via TCDCLink instead of TCIMGIO

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Per default specific graphic formats (PNG, GIF, JPG etc.) are converted using the TCIMGIO. Conversion jobs which are performed by TCIMGIO may experience some problems during the image rendering. Depending on the requirements we can choose which converter should be triggered for converting image files.

To get a better overview the list below shows the pros and cons for using TCDCLink instead of TCIMGIO for conversion.

Advantages for using the TCDCLink:

  • Better image rendering (TCIMGIO only supports B/W conversion).
  • More flexible, since it is controlled by the 'Shell Execute Printing'.

Disadvantages for using the TCDCLink:

  • Slower performance.
  • Multi-page files (E.g. Tif) can't be converted.

The decision which document conversion method should be used depends on the requirements.

  • If there is a requirement to convert files from different graphic formats (JPG, TIF, PNG, GIF etc.) and those images don't contain a wide color spectrum or are multi-paged (multi-page TIF), then it is suggested to use the TCIMGIO.
  • If there is a requirement to send colored graphics similar to the example images below, then it is strongly recommended to use the TCDCLink to get better looking results.

In this example we can see that using the TCDCLink for image conversion of a colored JPG can provide much better results, when converting the same using TCIMGIO you lose a lot of possible crucial information.


NOTE: Result is depending mainly on the source image. Examples below shows difference when converting a color JPG image. 

Original colored JPG as attached to the message.

Result after conversion using TCIMGIO

Result after conversion using TCDCLink


TCIMGIO is converting to pure B/W images while TCDCLink is using halftone Dithering which is better equipped to handle colors.


Below steps will describe what is needed to render image files through TCDCLink instead of TCIMGIO.

  1. Start the registry editor and navigate to this key: (this is needed for enabling gray-scaling)
    HKLM\System\CurrentControlSet\Control\Print\Printers\Topcall Fax to TCDC\PrinterDriverData\'halftonedither' = 1
  2. Navigate to the folder: C:\TCOSS\TCLP\script\ and make sure there is no script inside the folder which is named like the file extension which should be converted (E.g. no 'JPG.txt' for JPG files)
  3. Depending on the message flow, check the TCIMGIO32 settings of the involved TC/Link instance and set the 'InputExtensions' key for 'jpg' to empty.
    To do so please check the key:
    (This is an example for the file extension: JPG. For other graphic file extensions use the related 'FmtXXX' folder - for GIF use the 'FmtGIF', for BMP the 'FmtBMP' etc.)
  4. Install IrfanView (it is a freeware Image Viewer, but for commercial use a small license-fee is required. See link below in reference section.)
  5. Navigate to the shell execute of the TCDCLink and add the JPG extension.
    To do so go to below hive inside the registry:
    In this hive create a REG_SZ key named '.jpg' (or any other graphic file extension which is involved in the message flow) with the value:
    'C:\Program Files\IrfanView\i_view32.exe' '%1' /bpp=1 /print'
  6. After these changes please restart the involved TC/Link & TCDCLink. The document conversion and image rendering will now be done by the TCDCLink.


For x64 systems the Topcall registry key can be found here:

IrfanView will be installed in the following folder:
    C:\Program Files (x86)\IrfanView

Level of Complexity 


Applies to  

Product Version Build Environment Hardware
Kofax Communication Server All      


Link to an article on Wikipedia describing halftone dithering:

Link to IrfanView website: 


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