What is the correct way to print/export 600 DPI rasterized line art out of Illustrator?

[MichaelG1000]

When a print is made from Illustrator CC (2018) on my high-res laser printer (Xerox VersaLink C7000) at its highest resolution (600 DPI), Illustrator CC seems to be limiting the Postscript Native output to 400 DPI when it internally rasterizes the (postscript native) print. All color correction and other correction is turned off in the printer and I set Illustrator to preserve the CMYK values exactly - so, basically no color management CMYK -> CMYK.

The issue is that a thin line that is 0.18 pt (0.0025 in / 400 DPI) is the thinnest horizontal line that can be printed. There is a transition in thickness, a halving that occurs from 0.19 pt to 0.18 pt and then lines cannot get any thinner. Likewise, when transitioning from 0.35 pt to 0.36 pt, the lines double in thickness.

The maximum DPI that my Xerox VersaLink C700 laser printer can print in its highest resolution mode is a line at a true 600 DPI (0.12 pt). I verified this via Photoshop and can, in fact, print lines in multiples of 0.12 pt at 600 DPI, and they scale accordingly in thickness.

I am faced with two possibilities:

1) Set Illustrator to rasterize at 600 DPI for printing of vector art instead of 400 DPI, but I don't know how I can set this in Illustrator (again specifically for vector art such as line strokes).

2) Export the (completely) vector image containing the fine lines at 600 DPI, with each object being of a color where a primary is either 0 or 100/on or off (CMYK), in a format that can be imported into Photoshop, and then print from there. Photoshop seems to have no problems with a document that is 600 DPI when printing at my printer's native resolution. If I was to go this route, what would be the best image format to export in? PNG? PDF?, given that all pixels will be either 0/100 for each of the CMYK primaries.

Now, of course, I understand the limitations of this:

Each point can either be on or off with regard to the four primaries, C, M, Y, and K. So, there is 1-bit per primary available at 600 DPI. For example, if I want a green dot at 600 DPI, I would set the color to C=100, Y=100. All primaries must either be 0 or 100 at this resolution, since the printer is placing (or not placing) a single primary color dot for from one to four of its primary colors. So, the choice of colors at this DPI is: C, M, Y, R, G, B, K, and of course throwing a K=100 on top of the first six possibilities in the previous list, for a richer black with a color cast.

Thanks for any help or suggestions,

Michael

[Test Screen Name]

What makes you sure that Illustrator is rasterising at all? The essence of PostScript printing from AI is that it sends vectors to the printer. There are exceptions, such as transparency flattening or special effects.

[MichaelG1000]

@TestScreenName, 400 DPI is a very odd DPI value, especially for a 600 DPI laser printer. Photoshop is printing correctly at 600 DPI and Illustrator is not, with exactly the same configurations of the printer driver. It (Illustrator) is clearly printing lines that have been rasterized to 400 DPI and it is configured to do everything, since all features of the printer driver are turned off, from color correction to image enhancement.

Now, don’t get me wrong, the full printout dimensions are correct. However, at the point that vector lines with a thin stroke are converted to raster dots, a conversion process set to 400 DPI is used.

This conversion must happen somewhere, since laser printers are inherently raster based devices with a fixed physical DPI capability. I am convinced that this is happening within Illustrator and that raster and not vector data is shipped via postscript to the printer.

Perhaps someone more knowledgeable in this aspect of printing could chime in.

[Ton Frederiks]

Illustrator should not rasterize output when printing to  a PostScript printer.

Did you contact Xerox about this problem?

[Monika Gause]

I think it could be helpful to see that print.

[sarapixels]

I would personally export a png or jpeg at the desired resolution, and then print from that export, rather than trying to print directly out of Illustrator.

[jdanek]

"All color correction and other correction is turned off in the printer and I set Illustrator to preserve the CMYK values exactly - so, basically no color management CMYK -> CMYK."

What happens when you turn on color management?  Many users believe that their output device can print Illustrator CMYK percentages direct without printer managing color.  A 600d.p.i. output device will not be able to print fine lines like your .18pt; very difficult to print .25pt, not to mention the percentages in highlights and shadows. In order to image a .18pt line, your output resolution would have to be around 5480 d.p.i., this has been proven by you already with your inconsistent output variations.  But, let's say you can print the .18pt line, why not maximize your desktop printer's output by enabling the printer's print driver?

[Test Screen Name]

Using correct PPD? Pixel alignment in or off?