So when I do printer alignment tests I get excellent fine lines as seen below. But when I draw perfectly horizontal lines with the pen tool in illustrator they look horrible and very low quality. I think I have the settings right in Illustrator but obviously i'm missing something. Document is 300dpi, resolution is set to high, and ideas?

EDIT: Upon doing a little more research I discovered this was most likely due to my paintbrush lines not being vector. So my question is, how do I make these paintbrush lines vector so they print better?

enter image description here

1 Answer 1


Illustrator doesn't create a "document at 300dpi" There's no setting in Illustrator which controls the document PPI because Illustrator uses vector data and ppi is irrelevant. Raster images are imported/placed at whatever resolution they are set to and the Document Raster Effects (DRES) menu item has no bearing on anything other than glows/shadows/etc that are created by using the Effects menu within Illustrator. Changing the DRES setting does nothing to raster images within Illustrator.

Illustrator outputs Postscript data for printing.

Most end-use inkjet printers do not have a Postscript RIP (Raster Image Processor). Without a RIP, the printer will output the low resolution preview image rather than the actual postscript data, because the printer can not process the postscript data.

There is no way to correct this directly for a printer lacking a postscript RIP. However, there is a workaround you can use...

  • Save the AI file as a PDF, then print the PDF from Acrobat or Reader.

PDF/Acrobat is a software RIP and processes the actual postscript data to a high resolution preview image. Then the printer can print that high resolution image as opposed to the embedded low resolution preview image.

  • You can also merely open the AI file with Photoshop and then print from within Photoshop. Photoshop has an internal RIP and will output a high-resolution raster image an inkjet will understand.

  • The third option is to upgrade the printer to one with a Postscript RIP.

  • 1
    Thanks Scott that did the trick I ended up printing with Photoshop. Are there quality differences is the RIPs of Reader, Acrobat, Photoshop, or software like AccuRIP or do they all accomplish the same thing and provide the same quality?
    – Kay Dole
    Commented Feb 25, 2019 at 5:43
  • 1
    They'll all pretty much result in the same quality. I would somewhat lean towards the Acrobat route merely because it's all Adobe and Acrobat reads the postscript data directly -- actually Illustrator saves a PDF internally so there's no direct conversion. You can open AI files with Acrobat provided the PDF Compatibility was on when saving the AI file. But really, in the end, none of it makes a great deal of difference for an inkjet without a RIP.
    – Scott
    Commented Feb 25, 2019 at 5:51
  • Ok cool. I printed it out in Acrobat and PS and the PS version was much better. There was a lot of setting options in Acrobat maybe I didn't do something right though. Thanks again, was really stuck on this.
    – Kay Dole
    Commented Feb 25, 2019 at 6:17
  • @KayDole Hey, this is a technical case, but an important one, because things like this destroy the mood. Consider to accept the answer. It's only a click. Otherwise others cannot see there's an answer which contains something useful.
    – user82991
    Commented Feb 25, 2019 at 9:54

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