jump to navigation

Short Review: “Digital Capture After Dark” by Quintenz-Fiedler and Scholz, O’Reilly March 4, 2013

Posted by claudio in Uncategorized.
Tags: , , ,
add a comment

DCADCombine a busy life and short winter days and you don’t have a lot of natural day light to practice photography. So, the “Capture After Dark” part of the title interested me. While we’re talking about the title, let’s start with the bad. I kind of grew allergic of the “digital” adjective in photography books. Most of the time, it’s a cheap way to reprint some old material. And let face it, older photography books are just fine as a learning tool even when using a digital camera: the principles are the same. Books that take the “digital” identity seriously and add specific content (1/3 of this book) often fall in an other trap, by trying hard to be a manual for a specific version of a specific software package. As a result, when released, a big part of the book is either outdated or irrelevant (in the case you prefer to use other software, e.g. FOSS).

Luckily, the other two thirds of the book are about photography. As stated in the introduction, the information “is presented as a variety of techniques regarding equipment choice, technical approach, subject matter, and production practices”. This is certainly the case, and the book is useful and applicable, certainly if you’re relatively new to photography. On the other hand, if you already have replaced a camera because you used it to death, you won’t discover much new: yes, you need a tripod at night and warm clothing :) .

So, if you’re new to photography, I’ll give it a 3 stars out of 5 (1/3 of software manual killed it for me). If you’re not, maybe 2 out of 5: it’s not a bad book and certainly not something very technical of that goes deep in the artistic part of photography. Nevertheless, it’s very fast read and it’s good to see the bits you’ve learn in one document.

Screen Calibration on Ubuntu 12.04 with Spyder2 [workaround] May 6, 2012

Posted by claudio in Uncategorized.
Tags: , , , , , , ,
2 comments

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:

$ dispcalgui

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!

Perl devroom @FOSDEM2012: photos April 27, 2012

Posted by claudio in Uncategorized.
Tags: , , , , , , ,
1 comment so far

Finally I found the time to “develop” my Perl dev-room @ FOSDEM 2012 pictures (convert from camera RAW files to jpg). It was a very nice event. If you missed the Perl dev-room in the past year, you should really visit us in 2013. Or even better, give a talk.

In the pictures above you see Nicholas talking about Moose. He forgot his mac-VGA adaptor (ahum) so he ended up writing code on the blackboard (“the loudest syntax checker on earth”). Marc mixed some Haskell in his talk while Flavio showed some Javascript-powered Perl. Clément presented a Perl SSO solution and Erik showed us a open source accounting solution. Stefan introduced the PerlCommerce platform, while Ævar (a famous guy being the most mentioned name in Programming Perl, 4th ed!) talks about git-deploy (or rather git-undeploy :) ). Marius explained the marriage of Moose and MemCached.

As the organizer of the Perl dev-room, I had to attend to a few things during the talks. My excuses for not taking pictures of Mark’s and Guillaume’s talk (I was able to attend most of it, though). Sadly,  I didn’t had the time to photograph our fabulous Perl stand (although I have some pictures from last year): Wendy, Liz, Eric and all the other volunteers did a great job.

Thank you for a successful Perl FOSDEM presence.

The Program was as follows:

Welcome to the Perl devroom Claudio Ramirez AW1.121 09:00-09:05
Moose Primer Nicholas Perez AW1.121 09:05-09:25
Advanced Moose Techniques Nicholas Perez AW1.121 09:35-09:55
Perlude: a taste of Haskell in Perl Marc Chantreux AW1.121 10:05-10:45
Perlito Flávio Glock AW1.121 11:05-11:45
The LemonLDAP::NG Project Clément Oudot AW1.121 11:55-12:15
LedgerSMB: Open source accounting running on Perl Erik Huelsmann AW1.121 12:25-12:45
Modern PerlCommerce Stefan Hornburg AW1.121 13:25-14:05
Rapid real-world testing using git-deploy Ævar Arnfjörð Bjarmason AW1.121 14:15-14:35
POSIX::1003 Mark Overmeer AW1.121 15:00-15:40
The FusionInventory Project Guillaume Rousse AW1.121 15:50-16:10
Using Moose objects with Memcached Marius Olsthoorn AW1.121 16:20-16:40

Fosdem 2010 Impressions February 19, 2010

Posted by claudio in Uncategorized.
Tags: , , ,
4 comments

This year’s FOSDEM was great. Not only did we have a Perl stand, but we could also meet face to face with other Padre developers. Here follow some loose impressions of the weekend…

Hall of Distributions

Hacker Room

Open Solaris

Erik @ the Perl Stand (with a "tuit")

Perl/Padre developers Dave and Gabor

Catalan Perl Monger Alex (I forgot the name, please forgive me...)

O'Reilly

FSF Europe: respect!

BSDs

Gabor's CPAN talk

Salve's talk on Kaizendo.org

The Hat

Follow

Get every new post delivered to your Inbox.

Join 142 other followers