Are you saying you are doing both tests using Windows? One with Writer and one outside of Writer? Or is it a Windows vs. Linux question?
I run Ubuntu most of the time, and I prefer it. Let me say this about some Linux drivers for some printers. I have found that some color printerdrivers, HP color laser driver the worst, that some of these Linux drivers tend to get the colors for the images wrong. The HP Color Laserjet 2600, I hadbut now dead, tended to print the images more towards the brown shading. I have seen other Linux drivers do the same. Mostly HP printers. I have seen it on an Epson Artisan 810 inkjet printer, but not too noticeable unless you place the Windowsprint side-by-side with the Linux print.
Now, as I was reminded recently, you may have a choice of drivers types for your printer. I see the following options for Print > Properties > Device, in the Printer Language Type "box".
Automatic: PDF
Postscript (Level from driver)
Postscript Level 1
Postscript Level 2
Postscript Level 3
PDF
I had some problems printing a complex document with the default setting of "Automatic: PDF", yet, when I changed the option to Postscript Level 3, it worked fine.
So, please try Postscript Level 3 first, then try the others to seewhich one prints the best.
ALSO,
For my printers, I am able to access some printer controls that will modify the ink density and the color shading to make the printer's color prints look more like the color standards for the printing industry.