QTR-Quadtone RIP

Hi;
My early results with Quad rip show extremely  promising colour but
very unexpected grain.Normal printing on my Epson 2100 shows a
perfectly smooth result from the same file at the same size etc;
  My settings in Quad rip are-Epson 2100-model quad 2100-1440dpi-uni
directional-dither ordered- matte paper-all using the ultrachtome en 
matte warm setting. The file is sized for appropriate size at 300dpi.
The tests are only 6x4 inches so obviously no grain should be visible!
I am using Ilford Harmen FB Matte which is normally excellent except
for the expected 2100 colour shift.(without rip)
I have also tried other Quad paper settings ;dither; and also 2880 dpi
but with no improvement at all.
Any help will be much appreciated but i do have a gut feeling that the
image "coursens" WHEN IMPORTED into the Quad rip control panel.
 Thanks,Cliff