The problem is graininess, The problem is the paper is not flat – HP Designjet 4000 Printer series User Manual
Page 195
The problem is graininess
1.
Check that you are using appropriate print quality settings. See “How do I choose
print quality settings?” on page 130.
2.
Use the Image Diagnostics Print to find out more about the problem. See “How
do I use the Image Diagnostics Print?” on page 175.
The problem is the paper is not flat
If the paper does not lie flat when it comes out of the printer, but has shallow waves in
it, you are likely to see visible defects in the printed image, such as vertical stripes.
This can happen when you use thin paper that becomes saturated with ink.
Try changing to a heavier paper type: we recommend HP Heavyweight Coated Paper
or HP Productivity Photo Gloss for printing dense colors. See also “How do I choose
print quality settings?” on page 130.
193
The
problem
is print
quality