How to export grayscale image as grayscale in PDF?

[feklee]

Just realized that in the PDF, black text, in addition to K, also has components in the C, M, and Y channels. Indeed in the test print I realized that there are slight color fringes, which I originally blamed on the thick lamination.

Quote from Xara’s documentation on color separating: “When creating documents based on the default templates designed to be printed, such as US Letter or A4, then the shades of gray defined on the Color Line are defined to be tints of pure "K" black. So if you use these gray colors from the Color Line, you will get quality printed grays.”

I tested this with a new A4 document, and a rectangle, filled with Black from the Color Line. When exporting to PDF, I selected the Commercial Printing preset. When checking in Acrobat I see that the black box has components in the C, M, and Y channels.

Am I doing something wrong, or is this a bug / feature?

Workaround: PANTONE Process Black C maps to only the K channel.

[mwenz]

You are not doing anything wrong as regards the so-called shades of Black on the default color line. It is that the help file is a bit mis-leading. Yes, they will be "quality printed grays." But that doesn't mean they won't be a mix of CMYK or RGB values (depending upon the output intent).

Make all your text 100% K. Now, there is a lomg-standing bug in Xara products that can catch one out. That is, if one has an object defined as RGB of 0,0,0 and switches to the CMYK color model in the Color Editor, it will show as 100% K. It most definitely is not 100% K. It is a rich black composed of X amounts of CMY plus a high percentage of Black (if not 100% sometimes).

But with such an object selected, if you make the CMY sliders 0% if not already, then slide the K slider down a bit and back up it should work.

I use my own palette that avoids this issue.

[Albacore]

It's a feature! See my advice on #5 on this thread as I was thinking that you had a bitmap with text. This has always been one of the silly quirks of Xara. Just re-import your PDF and adjust K value and resave. For any bitmap that you want to be commercially printed you should start this process off in a Bitmap editor. You can use Grayscale or Lab but the best way is to using the "channel mixing" route. Just do a quick search "colour to BW + channel mixing". The reason for using this method you have much more control of the output and therefore better definition. Here a tut for P/Shop but I am sure that you could do the same in Gimp which is free to download: http://www.photoshopessentials.com/p...olor-channels/

[feklee]

mwenz, Albacore, thanks a lot for all the advice!