We are in the process of testing different options for sending faxes from within our C# code (receiving faxes is not necessary). One of those options is to use FAXCOMEXLib.

Without surprise, I've had pretty good success sending out black & white faxes with FAXCOMExLib. But we also have a requirement to support sending color faxes. So I execute the following code (just a snippet):

IFaxDocument oFaxDoc = new FaxDocumentClass();
oFaxDoc.Body = @"C:\Test\color_image.jpg";
oFaxDoc.ConnectedSubmit(m_oFaxServer);

The image is 24bit color, 1728x2304, 204x196 dpi.

For the most part, this process works (with a couple of small quirks) and the fax shows up in my "Windows Fax and Scan" outbox (I'm on Vista). The problem is the image has been dithered to a 1bit black & white image. I assume that what I see in "Windows Fax and Scan" is what is actually transmitted.

So is there a way to send a color fax using this technology? Are we missing a configuration option somewhere to make it work?