I've noticed that it's quite a challenge to get Kate to output black text when printing to pdf regardless of the color scheme (even using the default "Kate normal" and "Kate printing" color schemes). Why is that? Is there any way to overcome this?

I've had to resort to opening plain text documents in OpenOffice for this purpose which is less than ideal.

I can't confirm, does it print to ps ok?

I've just printed both a black and white and a colour (syntax highlighted) file to PDF from Kate and both have printed perfectly for me.

I wonder if you are expecting something really black. On my black and white file, the text of the file is slightly lighter than the filename which is printed at the same time. I presume this is built into the printer configuration.