[cups] Epson WF-6090: Varying line thickness on prints with horizontal lines

[Helge Blischke]

> Am 18.06.2018 um 12:24 schrieb David Rea <dave at daverea.com>:
> 
> Hello-
> 
> When printing pages with thin horizontal lines from my Linux box, I see
> visible variations in the thickness of the lines from top to bottom:
> 
> https://photos.app.goo.gl/6j799q2Sny2kx9RM9
> 
> Running an Epson WF-6090 inkjet set up on my Ubuntu 16.04 workstation
> running CUPS 2.1.3 and a PPD file downloaded via Epson's
> website: epson-inkjet-printer-escpr 1.6.20-1lsb3.2.
> 
> The output file is a PDF, generated by PDFkit. The horizontal line
> thickness is uniformly 0.1mm, or 0.283465 PDF pixels. The only resolution
> option in the printer's settings dialog is 300DPI, and the same visible
> variations occur when I round the line thickness to the nearest 1/300th of
> an inch (0.35 PDF pixels).
> 
> Printing either file from Adobe Reader on Windows 7, using Epson-supplied
> drivers, results in uniform visible thickness:
> 
> https://photos.app.goo.gl/MfKauNQ3Qjffek688
> 
> I've tried varying paper and quality settings, running from the generic
> inkjet PPDs, and printing from both Chrome and evince under Ubuntu (all
> "scale" and "fit" options disabled, in both cases), all with identical
> results. Something appears to be resampling the PDF, possibly during
> rasterization?
> 
> Any assistance with this issue or guidance on further troubleshooting would
> be greatly appreciated!
> 
> Thanks,
> Dave
> _______________________________________________

As this printer – according to Epson’s web site(s) – natively supports a variety of printer languages
(ESC/P, PCL5 emulation, PostScript 3, …) I’d need the following information to dig into the issue:
(1)	the PPD you use
(2)	the portion of the error_log for a job that exhibits the issue (with debug logging switched on)
(3)	the input PDF

To produce the information as of (2) do the following:
–	execute 
	cupsctl —debug-logging
–	print the input PDF from the command line using the lp command
–	save the job ID and extract the job specific log lines from the error_log by executing the
	commands
#!/usr/bin/perl -w
$jid=shift;
system ("grep \"Job $jid\" /var/log/cups/error_log.O | grep -v 'Set job-printer-state-message to' > /tmp/temp.log");
system ("grep \"Job $jid\" /var/log/cups/error_log | grep -v 'Set job-printer-state-message to' >> /tmp/temp.log");
system ("view /tmp/temp.log“);

as a Perl script.

Helge

PS: you may send me the information off the list, as the list eliminates all attachments that are not plain text files.