将 CMYK tif 图像打印到 WPF 中的 CMYK pdf 会失去颜色

Question

I have a tiff file saved in CMYK, which I'm loading into an image in WPF. I'm then adding the image to a document and saving it to a CMYK PDF using the Adobe PDF print driver. The Image in the PDF document is less vibrant than the original image. I've tried many settings for the PDF printer to no avail. If I save to the PDF in an RGB color space, the color is preserved perfectly, as far as I can tell. Alternatively, I can create a CMYK PDF file within Adobe Acrobat from the same CMYK image and the quality is perfect.

My guess is that somewhere between loading the image in WPF and printing the image, I'm getting RGB pixels, which are then converted back to CMYK, losing the original color information, but I really don't know. When the bitmap image is loaded, I can see in the debugger that the format is Cmyk32, so maybe the image control, the page or the document is rendering it in RGB when going through XPS. I can't tell. Does anyone have any ideas? Here's a code sample I created to show the issue.

// select printer and get printer settings
PrintDialog printDialog = new PrintDialog();

if (printDialog.ShowDialog() != true)
{
    return;
}

LocalPrintServer ps = new LocalPrintServer();

// Get the default print queue
PrintQueue pq = ps.GetPrintQueue(printDialog.PrintQueue.FullName);

// create a document
FixedDocument document = new FixedDocument();
document.DocumentPaginator.PageSize = 
    new Size(printDialog.PrintableAreaWidth, printDialog.PrintableAreaHeight);

// create a page
FixedPage page = new FixedPage
{
    Width = document.DocumentPaginator.PageSize.Width,
    Height = document.DocumentPaginator.PageSize.Height
};

BitmapImage bi = new BitmapImage();
bi.BeginInit();
bi.UriSource = new Uri("testcmyk.tif", UriKind.RelativeOrAbsolute);
bi.CacheOption = BitmapCacheOption.OnLoad;
bi.CreateOptions = BitmapCreateOptions.PreservePixelFormat;
bi.EndInit();

Image image = new Image
{
    Source = bi
};

page.Children.Add(image);

PageContent content = new PageContent
{
    Child = page
};

document.Pages.Add(content);

XpsDocumentWriter xpsdw = PrintQueue.CreateXpsDocumentWriter(pq);
xpsdw.Write(document, printDialog.PrintTicket);

I have seen a few other questions about using CMYK in WPF, but I haven't found this exact issue. I really need the CMYK pdf to submit to a professional print company, but the artwork is losing color going through the software. The problem gets worse (looks worse) when the tiff file also has transparency.

Edit

After trying out various things to track down where the problem is occurring, I decided to just save out the XPS file. In doing so, I found something quite disheartening. Here's a code snippet:

using (FileStream stream = new FileStream("test.xps", FileMode.Create))
{
    Package package = Package.Open(stream, FileMode.Create);
    using (XpsDocument xpsDoc = new XpsDocument(package, System.IO.Packaging.CompressionOption.NotCompressed))
    {
        XpsDocumentWriter xpsdw = XpsDocument.CreateXpsDocumentWriter(xpsDoc);
        xpsdw.Write(image);
    }
}

I'm passing in the same image here as in the first code snippet just to see what the XpsDocumentWriter will do with it. When I opened the resulting.xps file with 7zip, I discovered that the original tiff file was gone, and had been converted to a png, If I'm understanding the printing system correctly, my original CMYK tiff file never makes it to the pdf printer. as it goes through the XPS system to get there? is there any remedy for this? Is there any way for XPS to retain the original image? Is it perhaps even before this stage that the problem occurs? Please help!

Answer 1

If it is an option for you, you could consider using an Imaging Toolkit like the LEADTOOLS Imaging SDK which has classes for handling the CMYK color space. (Disclaimer: I am an employee of the vendor of this toolkit)

The toolkit has a LoadCmykPlanes and SaveCmykPlanes methods that can be used to convert your TIFF image to a CMYK PDF without affecting the CMYK planes.

The code for this is as follows:

// take CMYK data from file inputCmykTiff and save it as PDF into file outputCmykPdf
Leadtools.Codecs.RasterCodecs codecs = new RasterCodecs();
Leadtools.RasterImage imageWithPlanes = codecs.LoadCmykPlanes(inputCmykTiff, 0, 1);
codecs.SaveCmykPlanes(imageWithPlanes, outputCmykPdf, RasterImageFormat.RasPdfCmyk, 8, 1, CodecsSavePageMode.Overwrite);

As the result will depend on your input images, I'd suggest testing with the free evaluation to see if this produces a good result.