On an Officejet Pro L7580 I'm getting narrow vertical black lines on the image when I print photos. These do not appear on the sheet when printing documents or graphics or scanned images, only within the photo itself when it is printed. Printheads have been changed, the unit unplugged ('reset') alignment carried out, etc. etc.
The original jpg files look clean, ie. no vertical lines can be seen on the original image when viewed on the monitor prior to printing.