Tags: argyll, bug, dispcalgui, fosdem, Perl, photography, Ubuntu, workaround
The bad news: the default colour calibration wizard on Ubuntu 12.04 has a bug: awful magenta cast on some screens. Fine on others.
The good news: it works flawlessly using the (graphical) alternative below.
As a enthusiastic photographer (see my latest Perl Fosdem pictures) I am very positive about the colour management integration in the latest Ubuntu (12.04). Sure, colour calibration was possible before, but now it’s an integral part of the system and not a simple add-on. Ubuntu++
Once the reviews are in, I will probably buy the ColorHug open source hardware calibration device. In the meantime I borrowed an old Spyder2 (express) from my father-in-law. I do not recommend buying new devices from Colorvision. The company is known to be very antagonistic to free and open source software. But, if you already have the hardware in a drawer it’s better to use it.
Once you plug in the device, the “Calibration” button will activate and the necessary packages will be installed. However, for this HOWTO it’s easier just to install the software (and its dependencies) from a shell window:
$ sudo apt-get install gnome-color-manager
(This install argyll as a dependency that does the real calibration beneath the GUI.)
This step is only applicable if you have a Spyder 2 device. As mentioned above, the company is not FOSS-friendly and doesn’t even provide technical specifications. You will need the firmware of the device from the Windows driver. If you trust me, you can get mine here [MD5: 007ac5705a3a8ed7edf01569700e6ebf]. Put it in the .local/share/color directory in your home directory (create the needed directories if not present). It was extracted from the 2.3.6 Windows driver for the Spider2 Express (the latest at the time of writing). If you want to create the file yourself, see here. In short: you’ll need the driver CD. If you don’t have it or want/need a more up-to-date version, you’ll need to install the driver and feed the generated .dll to spyd2en:
spyd2en -v ./CVSpyder.dll
In the GUI (Dash -> Applications -> Color, or simply type “color” and click the icon), if you select your screen and the “Calibrate…”, the steps offered by the wizard are straight forward. Very easy. While it worked great on the computer of my better half, the generated profile on my own laptop (attached to an external screen) had a terrible magenta cast. Not of the type “your eyes will adapt to it”.
After investigating and looking closely at the profile, it was clear that the profile used a 6500K white balance, instead of the 5000K requested in the wizard (it’s called “Photography and graphics” there). Furthermore, the wizard offered 3 calibrations options: 4, 10 and 20 minutes depending on the desired accuracy. While I chose 4 minutes for testing purposes, the calibration took a long time (an hour or longer). Also, the advanced output in the calibration window (hidden by default) categorised the screen as CRT while it’s a LCD. Because of this, I don’t think the problem is tied to the specific firmware (running the latest available) of the hardware, but rather to gnome-color-manager integration with the device and maybe certain configurations. I don’t have other calibration devices available to test. Bug reported.
dispcalGUI is a OS-agnostic alternative to gnome-color-manager and in fact – just as gnome-color-manager – and GUI on top argyll. Just download the deb (the most recent deb for Ubuntu 11.10 works fine on 12.04). If you double click it, the Ubuntu Software Manager will launch and perform the installation (or just use “dpkg -i” if you are a Debianista at heart).
Now, launch the dispcalGUI application from the Dash or just open a terminal (Ctrl + Alt + t) and type:
Select the Photography profile, your screen (if you have a multi monitor setup) and probe your device (by clicking on the “recycle” arrows) and give your profile a more recognisable name and a location. I use brand_model_calibrationDevice, e.g. Samsung_SyncMaster2443FW_Spyder2Express). Click on Calibrate and Profile and go read a book or take some pictures (it will take a lot longer than 20 minutes, probably an hour). If you wish you can skip the white point and black level, YMMV.
Now go back to the Ubuntu Color Settings as above and add the new created profile by selecting your screen, then click “Add profile”, select other and choose the path you save the monitor profile.
Your monitor is now calibrated!
Bug: Ubuntu 8.10 and older nvidia video cards October 31, 2008Posted by claudio in Uncategorized.
Tags: bug, nvidia, ubuntu bug, workaround
EDIT: Workaround not longer needed as the drives has been fixed on the Ubuntu repositories.
Yeah. New Ubuntu release. Traditionally, this means upgrading without reading the release notes.
<Curse>. This is what it says (I read today):
nVidia “legacy” video support
The 71 and 96 series of proprietary nVidia drivers, as provided by the nvidia-glx-legacy and nvidia-glx packages in Ubuntu 8.04 LTS, are not compatible with the X.Org included in Ubuntu 8.10. Users with the nVidia TNT, TNT2, TNT Ultra, GeForce, GeForce2, GeForce3, and GeForce4 chipsets are affected and will be transitioned on upgrade to the free nv driver instead. This driver does not support 3D acceleration.
Users of other nVidia chipsets that are supported by the 173 or 177 driver series will be transitioned to the nvidia-glx-173 or nvidia-glx-177 package instead. However, unlike drivers 96 and 71, drivers 173 and 177 are only compatible with CPUs that support SSE (e.g. Intel Pentium III, AMD Athlon XP or higher). Systems with older CPUs will also be transitioned to the nv driver on upgrade.
The “nv” driver does not support my dual-monitor 2 x 1680×1050 resolution. After looking for some workarounds (compiling kernels) and at the point of a downgrade to 8.04, I found an easy solution.