I have been running into problems with Plasma's printing backend. I cannot print colour documents in greyscale and I cannot print on custom paper sizes. However applications that use the gtk print dialogue work fine, such as Firefox or Abiword.

I do like using Okular and Gwenview, but I have been forced to use other applications because of these deficiencies in printing. Is there a way to use the gtk print dialogue for KDE applications instead?