It sounds like you have an empty black cartridge, which is not used for photo
printing. Try printing a diagnostic test page as shown at the following:
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=bpd05291
If there is not black print in the self test page your black cartridge is
probably empty. It is also possible that your spittoon is full. If the black
cartridge is not empty check the following for instructions on cleaning the
spittoon: http://h20015.www2.hp.com/en/document.jhtml?lc=en&docName=bpa02019
Regards,
Bob Headrick, not speaking for my employer HP