Hello J T, thanks for reporting that this is still a problem. I had originally filed this report in 2012, but since it never moved forward I just resigned and kept using the HPIJS driver, which produces much better (in terms of visually accurate) output. However, Till Kamppeter says that Ubuntu is actively phasing out the HPIJS driver. This means that the HPCUPS driver needs to be improved/fixed.
This bug is (upstream) assigned to Suma Byrappa, so he/she should be the person to contact. @Suma Byrappa: Can you confirm that hpcups uses different halftoning algorithms (amplitude vs. frequency modulation). Why is this? Why does it mainly concern greyscale prints, not color? How about adding an option of selecting the algorithm in the officially maintained driver (which is hpcups, as I understand)? Thanks for your support! -- You received this bug notification because you are a member of Desktop Packages, which is subscribed to hplip in Ubuntu. https://bugs.launchpad.net/bugs/1036236 Title: hpcups and hpijs driver use different rasterization Status in HPLIP: Confirmed Status in hplip package in Ubuntu: Won't Fix Bug description: HPLIP provides two drivers for the Laserjet 1515n: hpcups and hpijs: - hp-color_laserjet_cp1515n-hpijs-pcl3.ppd - hp-color_laserjet_cp1515n-pcl3.ppd The new hpcups shall replace the old hpijs, however, it produces very different rasterization results, resulting in a radically different visual impression. Differences are especially prominent for greyscale prints. Hpcups produces "amplitude modulation" halftones (dots of different sizes at fixed locations). When resolution is set to "Normal", the size of these dots is so large that contours cannot be reproduced with reasonable detail. Heavy aliasing can be easily seen in the circle contours on the Ubuntu Printer test page. Printing photographs in greyscale mode yields badly rasterized images like those known from low-quality newspaper prints (dot pattern is so prominent it dominates image contours). Artifacts are reduced, but still visible at resolution "Best". In contrast, hpijs produces "frequency modulation" halftones with stochastic dithering (small-sized dots placed at varying densities). At resolution "Normal", it produces evenly colored areas with reasonably sharp edges. Circle contours on the Ubuntu Printer test page appear continuous. Photographs are reproduced at a a much higher fidelity as with the hpcups driver. Questions: 1. Why do the two drivers use different rasterization? 2. Why is the result of rasterization so bad in the hpcups driver, set at resolution "Normal, Greyscale"? Note: Both drivers produce acceptable color prints with much fewer artifacts visible, even at resolution "Normal". ProblemType: Bug DistroRelease: Ubuntu 12.04 Package: hplip 3.12.2-1ubuntu3.1 ProcVersionSignature: Ubuntu 3.2.0-29.46-generic 3.2.24 Uname: Linux 3.2.0-29-generic i686 ApportVersion: 2.0.1-0ubuntu12 Architecture: i386 CurrentDmesg: [ 63.368304] init: plymouth-stop pre-start process (1700) terminated with status 1 Date: Mon Aug 13 16:38:16 2012 Lpstat: device for Farblaser: hp:/net/HP_Color_LaserJet_CP1515n?zc=NPIE56824 MachineType: exone D156200 Papersize: letter PpdFiles: Farblaser: HP Color LaserJet cp1515n pcl3, hpcups 3.12.2 ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-3.2.0-29-generic root=/dev/mapper/lvmvg-Root ro quiet splash vt.handoff=7 SourcePackage: hplip UpgradeStatus: Upgraded to precise on 2012-04-26 (108 days ago) dmi.bios.date: 04/23/2004 dmi.bios.vendor: FUJITSU SIEMENS // Phoenix Technologies Ltd. dmi.bios.version: 4.06 Rev. 1.09.1562 dmi.board.name: D1562 dmi.board.vendor: FUJITSU SIEMENS dmi.board.version: S26361-D1562 dmi.chassis.type: 6 dmi.chassis.vendor: exone dmi.modalias: dmi:bvnFUJITSUSIEMENS//PhoenixTechnologiesLtd.:bvr4.06Rev.1.09.1562:bd04/23/2004:svnexone:pnD156200:pvr:rvnFUJITSUSIEMENS:rnD1562:rvrS26361-D1562:cvnexone:ct6:cvr: dmi.product.name: D156200 dmi.sys.vendor: exone To manage notifications about this bug go to: https://bugs.launchpad.net/hplip/+bug/1036236/+subscriptions -- Mailing list: https://launchpad.net/~desktop-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~desktop-packages More help : https://help.launchpad.net/ListHelp
