Q: I have the code to render PDF to CMYK TIFF but the result image'
color is a bit different from the source pdf file.
// Based on your PDFDraw sample ...
ObjSet hint_set = new ObjSet();
Obj cmyk_hint = hint_set.CreateDict();
cmyk_hint.PutName("ColorSpace", "CMYK");
try
{
draw.SetImageSmoothing(true);
// A) Open the PDF document.
using (PDFDoc doc = new PDFDoc(@"in.pdf"))
{
// Initialize the security handler, in case
the PDF is encrypted.
doc.InitSecurityHandler();
// B) The output resolution is set to 300 DPI.
draw.SetDPI(300);
// C) Rasterize the first page in the document
and save the result as TIFF.
Page pg = doc.GetPage(1);
draw.Export(pg, output_path + "out.tif",
"TIFF", cmyk_hint);
}
}
catch (PDFNetException e) {
Console.WriteLine(e.Message);
}
Why is the color different and what can I do about it?
-------------------------
A: The color seems to be very close on our machines. You may see
different results because of different color calibration and different
ICC profiles in Acrobat/Tiff viewer? Proper color management is a
quite complicated topic and requires lots of patience to make it
work.
In PDFNet you can use PDFNet.SetColorManagement(PDFNet.CMSType.e_lcms)
to enable color management and use
PDFNet.SetDefaultDeviceCMYKProfile(…) and
PDFNet.SetDefaultDeviceRGBProfile(…) to select different color
profiles. Selecting different ICC profiles will result in different
colors in the output image. If you use the same profiles in all
applications you should get 'roughly' the same color (different CMS
may produce different results so there is no 'perfect' solution).