HP 2000CP 2500CP - Manual (Page 158)

6-16 Image Quality HP DesignJet CP Series Printers
Only replace one component at a time and
check if the problem has gone before
replacing another component. Using this
procedure you will be able to determine
exactly which component failed.
Test Pattern 5: Color Variation Test
This test produces four boxes; black, blue, cyan and yellow. In each box
there are three horizontal bands, the two outer bands are 100% shade, the
inner band is shaded from 100% scaling to 75%.
The purpose of this test is to determine at what percent the middle shading
becomes visible from the two outer bands. The best way to do this is to cover
the box with a piece of paper and slide the paper horizontally across the box.
Stop as soon as you see a different shade in the middle box. You can then
determine the percentage scaling from the figure at the top of the box.
Example E (Correct)
Example F (Incorrect)