Type Default Value Read Only Description

[Visual Basic]
false No Whether to apply overprint.




Overprint is a way of combining colors when dealing with subtractive color spaces such as CMYK or DeviceN.

Normally when one color is painted over another it replaces the underlying color. So a yellow over a magenta becomes yellow. If Overprint is set, then the top color may be placed over the top of the base color. So yellow over magenta becomes a mixture of both yellow and magenta inks, which creates red. This can be useful for printing purposes.

If Overprint is true, and NamedSeparation is blank, an overprint preview is created that is designed to simulate the look of a document when inks are overprinted according to the details in the pdf. For more information on overprinting, please see the Adobe PDF Specification.




The following example shows the effect that this parameter has on PDF rendering.


using (Doc doc = new Doc()) {   // Open document with overprint   doc.Read(Server.MapPath("../mypics/Overprint.pdf"));   // Render the document (we need to go to CMYK for overprint)   doc.Rendering.ColorSpace = XRendering.ColorSpaceType.Cmyk;   doc.Rendering.Overprint = true;   doc.Rendering.IccRgb = "device";   doc.Rendering.IccGray = "device";   doc.Rendering.IccCmyk = "device";   doc.Rendering.IccOutput = "device";   // Put image back into another PDF and render the document as RGB   // (so that we can see the effect of the overprint in RGB)   Doc theRgb = new Doc();   theRgb.AddImageData(doc.Rendering.GetData(".tif"), 1);   doc.Clear();   theRgb.Rendering.DotsPerInch = 36;   theRgb.Rendering.ColorSpace = XRendering ColorSpaceType.Rgb;   theRgb.Rendering.Save(Server.MapPath("RenderingOverprint.png"));   theRgb.Clear(); }