I see the Color → B/W part of this on noble (cups 2.4.7-1.2ubuntu7.14, libcupsfilters 2.0.0-0ubuntu7.2) with a driverless Brother MFC-J4335DW. It happens both on the cups-browsed `implicitclass://` queue and on an `lpadmin -m everywhere` queue.
There are two causes. **1. The client re-adds the default color mode.** A job with `ColorModel=Gray` also carries `print-color-mode=color`, the queue default, and `print-color-mode` wins downstream. cupsd doesn't add it: the same job sent with ipptool gets no `print-color-mode`, because the upstream fix b0f1a00 is in 2.4.7. libcups turns `print-color-mode- default` into a destination option, and `lp` merges it into the job without checking `ColorModel` (strace confirms `lp` sends it). Chrome's B&W jobs show the same pair. This is unfixed upstream too: https://github.com/OpenPrinting/cups/issues/1778. ``` lp -d QUEUE -o job-hold-until=indefinite -o ColorModel=Gray t.txt # Get-Job-Attributes on the held job: # ColorModel = Gray # print-color-mode (keyword) = color cancel QUEUE-<id> ``` That fits "defaults set within cups work, settings while printing are ignored". **2. libcupsfilters 2.0.0 renders sRGB for URF/PWG output** even when `print-color-mode=monochrome`. This is fixed upstream in 2.1.0 (libcupsfilters #38 / #125), and backport requested in bug 2171466. A working workaround is a dedicated queue with `print-color-mode- default=monochrome` plus a grayscale `cupsPreFilter` keyed on `application/vnd.universal-input`. Details are in bug 2171466. **AI Disclosure:** Claude wrote this for me after we spent an hour or so getting black & white printing working for me. One of several issues that made it hard to puzzle out. ** Bug watch added: github.com/OpenPrinting/cups/issues #1778 https://github.com/OpenPrinting/cups/issues/1778 -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2142461 Title: cups printing does not respect certain options while printing To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/cups/+bug/2142461/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
