Kyocera FS1320D needs resolution set in ghostscript filter
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
cups-filters (Ubuntu) |
Fix Released
|
Critical
|
Unassigned |
Bug Description
Chrisl and kens in the #ghostscript channel figured out what causes these incredible processing slow-downs when feeding ghostscript postscript containing images to the Kyocera FS 1320D (and most likely C1020 MFP, I didn't have it here to test this...).
The printer states that it is capable of 1200x1200 dpi. Because ghostscript internally uses 720dpi to render those images, it would be desirable to be able to change this to something like 300dpi or more generally to something where "Printer Resolution" mod "Image Resolution" == 0.
This is probably a good idea for most printers, as this simple change brought down my printing time from minutes to less than a second. (transmitting time + processing time; physical output takes longer of course...)
description: | updated |
Changed in cups-filters (Ubuntu): | |
milestone: | none → ubuntu-12.04 |
importance: | Undecided → High |
status: | New → In Progress |
Changed in cups-filters (Ubuntu): | |
status: | In Progress → Fix Committed |
Changed in cups-filters (Ubuntu): | |
status: | Triaged → In Progress |
It looks like the poppler pstops tool defaults to 300 dpi, compared to Ghostscript's ps2write's 720dpi. Normally, this would not matter (both will always try to preserve scalability whenever possible), but when flattening transparency, the resulting image is created at the requested resolution. Both flatten PDF transparency groups to images in a similar fashion.
I suspect a number of the performance issues with Postscript printers stem from this, so the simple "fix" is to add "-r300" to the GS command line to get comparable output to the pstops.
As stated above, a nice enhancement would be to choose a resolution which is an integer diviser of the actual printer resolution: so for 600, 1200 and 2400 dpi, 300 is a good setting. For 720, 1440, 2880 dpi, 360 would be a good setting.
FWIW, it might be informative to assess the actual operating resolution of the poppler based "toraster" utility in the cups workflow, and see if that was also using a fixed (default?) resolution.